Merge branch 'release/2.9.0' into 'stable'

Release/2.9.0

See merge request pleroma/pleroma!4331

46 files changed, 1177 insertions, 502 deletions

diff --git a/lib/mix/tasks/pleroma/emoji.ex b/lib/mix/tasks/pleroma/emoji.ex
index 8b9c921c8..b656f161f 100644
--- a/lib/mix/tasks/pleroma/emoji.ex
+++ b/lib/mix/tasks/pleroma/emoji.ex
@@ -93,6 +93,7 @@ defmodule Mix.Tasks.Pleroma.Emoji do
         )
 
         files = fetch_and_decode!(files_loc)
+        files_to_unzip = for({_, f} <- files, do: f)
 
         IO.puts(IO.ANSI.format(["Unpacking ", :bright, pack_name]))
 
@@ -103,17 +104,7 @@ defmodule Mix.Tasks.Pleroma.Emoji do
             pack_name
           ])
 
-        files_to_unzip =
-          Enum.map(
-            files,
-            fn {_, f} -> to_charlist(f) end
-          )
-
-        {:ok, _} =
-          :zip.unzip(binary_archive,
-            cwd: String.to_charlist(pack_path),
-            file_list: files_to_unzip
-          )
+        {:ok, _} = Pleroma.SafeZip.unzip_data(binary_archive, pack_path, files_to_unzip)
 
         IO.puts(IO.ANSI.format(["Writing pack.json for ", :bright, pack_name]))
 
@@ -201,7 +192,7 @@ defmodule Mix.Tasks.Pleroma.Emoji do
 
     tmp_pack_dir = Path.join(System.tmp_dir!(), "emoji-pack-#{name}")
 
-    {:ok, _} = :zip.unzip(binary_archive, cwd: String.to_charlist(tmp_pack_dir))
+    {:ok, _} = Pleroma.SafeZip.unzip_data(binary_archive, tmp_pack_dir)
 
     emoji_map = Pleroma.Emoji.Loader.make_shortcode_to_file_map(tmp_pack_dir, exts)
 
diff --git a/lib/pleroma/constants.ex b/lib/pleroma/constants.ex
index 2828c79a9..3762c0035 100644
--- a/lib/pleroma/constants.ex
+++ b/lib/pleroma/constants.ex
@@ -20,7 +20,8 @@ defmodule Pleroma.Constants do
       "deleted_activity_id",
       "pleroma_internal",
       "generator",
-      "rules"
+      "rules",
+      "language"
     ]
   )
 
@@ -36,10 +37,12 @@ defmodule Pleroma.Constants do
       "updated",
       "emoji",
       "content",
+      "contentMap",
       "summary",
       "sensitive",
       "attachment",
-      "generator"
+      "generator",
+      "language"
     ]
   )
 
@@ -100,7 +103,8 @@ defmodule Pleroma.Constants do
       "Announce",
       "Undo",
       "Flag",
-      "EmojiReact"
+      "EmojiReact",
+      "Listen"
     ]
   )
 
diff --git a/lib/pleroma/ecto_type/activity_pub/object_validators/content_language_map.ex b/lib/pleroma/ecto_type/activity_pub/object_validators/content_language_map.ex
new file mode 100644
index 000000000..dcdab19f8
--- /dev/null
+++ b/lib/pleroma/ecto_type/activity_pub/object_validators/content_language_map.ex
@@ -0,0 +1,49 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2023 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.EctoType.ActivityPub.ObjectValidators.ContentLanguageMap do
+  use Ecto.Type
+
+  import Pleroma.EctoType.ActivityPub.ObjectValidators.LanguageCode,
+    only: [good_locale_code?: 1]
+
+  def type, do: :map
+
+  def cast(%{} = object) do
+    with {status, %{} = data} when status in [:modified, :ok] <- validate_map(object) do
+      {:ok, data}
+    else
+      {_, nil} -> {:ok, nil}
+      {:error, _} -> :error
+    end
+  end
+
+  def cast(_), do: :error
+
+  def dump(data), do: {:ok, data}
+
+  def load(data), do: {:ok, data}
+
+  defp validate_map(%{} = object) do
+    {status, data} =
+      object
+      |> Enum.reduce({:ok, %{}}, fn
+        {lang, value}, {status, acc} when is_binary(lang) and is_binary(value) ->
+          if good_locale_code?(lang) do
+            {status, Map.put(acc, lang, value)}
+          else
+            {:modified, acc}
+          end
+
+        _, {_status, acc} ->
+          {:modified, acc}
+      end)
+
+    if data == %{} do
+      {status, nil}
+    else
+      {status, data}
+    end
+  end
+end
diff --git a/lib/pleroma/ecto_type/activity_pub/object_validators/language_code.ex b/lib/pleroma/ecto_type/activity_pub/object_validators/language_code.ex
new file mode 100644
index 000000000..4779deeb0
--- /dev/null
+++ b/lib/pleroma/ecto_type/activity_pub/object_validators/language_code.ex
@@ -0,0 +1,27 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2023 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.EctoType.ActivityPub.ObjectValidators.LanguageCode do
+  use Ecto.Type
+
+  def type, do: :string
+
+  def cast(language) when is_binary(language) do
+    if good_locale_code?(language) do
+      {:ok, language}
+    else
+      {:error, :invalid_language}
+    end
+  end
+
+  def cast(_), do: :error
+
+  def dump(data), do: {:ok, data}
+
+  def load(data), do: {:ok, data}
+
+  def good_locale_code?(code) when is_binary(code), do: code =~ ~r<^[a-zA-Z0-9\-]+\z$>
+
+  def good_locale_code?(_code), do: false
+end
diff --git a/lib/pleroma/emoji/pack.ex b/lib/pleroma/emoji/pack.ex
index 785fdb8b2..c58748d3c 100644
--- a/lib/pleroma/emoji/pack.ex
+++ b/lib/pleroma/emoji/pack.ex
@@ -24,12 +24,13 @@ defmodule Pleroma.Emoji.Pack do
 
   alias Pleroma.Emoji
   alias Pleroma.Emoji.Pack
+  alias Pleroma.SafeZip
   alias Pleroma.Utils
 
   @spec create(String.t()) :: {:ok, t()} | {:error, File.posix()} | {:error, :empty_values}
   def create(name) do
     with :ok <- validate_not_empty([name]),
-         dir <- Path.join(emoji_path(), name),
+         dir <- path_join_name_safe(emoji_path(), name),
          :ok <- File.mkdir(dir) do
       save_pack(%__MODULE__{pack_file: Path.join(dir, "pack.json")})
     end
@@ -65,43 +66,21 @@ defmodule Pleroma.Emoji.Pack do
           {:ok, [binary()]} | {:error, File.posix(), binary()} | {:error, :empty_values}
   def delete(name) do
     with :ok <- validate_not_empty([name]),
-         pack_path <- Path.join(emoji_path(), name) do
+         pack_path <- path_join_name_safe(emoji_path(), name) do
       File.rm_rf(pack_path)
     end
   end
 
-  @spec unpack_zip_emojies(list(tuple())) :: list(map())
-  defp unpack_zip_emojies(zip_files) do
-    Enum.reduce(zip_files, [], fn
-      {_, path, s, _, _, _}, acc when elem(s, 2) == :regular ->
-        with(
-          filename <- Path.basename(path),
-          shortcode <- Path.basename(filename, Path.extname(filename)),
-          false <- Emoji.exist?(shortcode)
-        ) do
-          [%{path: path, filename: path, shortcode: shortcode} | acc]
-        else
-          _ -> acc
-        end
-
-      _, acc ->
-        acc
-    end)
-  end
-
   @spec add_file(t(), String.t(), Path.t(), Plug.Upload.t()) ::
           {:ok, t()}
           | {:error, File.posix() | atom()}
   def add_file(%Pack{} = pack, _, _, %Plug.Upload{content_type: "application/zip"} = file) do
-    with {:ok, zip_files} <- :zip.table(to_charlist(file.path)),
-         [_ | _] = emojies <- unpack_zip_emojies(zip_files),
+    with {:ok, zip_files} <- SafeZip.list_dir_file(file.path),
+         [_ | _] = emojies <- map_zip_emojies(zip_files),
          {:ok, tmp_dir} <- Utils.tmp_dir("emoji") do
       try do
         {:ok, _emoji_files} =
-          :zip.unzip(
-            to_charlist(file.path),
-            [{:file_list, Enum.map(emojies, & &1[:path])}, {:cwd, String.to_charlist(tmp_dir)}]
-          )
+          SafeZip.unzip_file(file.path, tmp_dir, Enum.map(emojies, & &1[:path]))
 
         {_, updated_pack} =
           Enum.map_reduce(emojies, pack, fn item, emoji_pack ->
@@ -292,7 +271,7 @@ defmodule Pleroma.Emoji.Pack do
   @spec load_pack(String.t()) :: {:ok, t()} | {:error, :file.posix()}
   def load_pack(name) do
     name = Path.basename(name)
-    pack_file = Path.join([emoji_path(), name, "pack.json"])
+    pack_file = path_join_name_safe(emoji_path(), name) |> Path.join("pack.json")
 
     with {:ok, _} <- File.stat(pack_file),
          {:ok, pack_data} <- File.read(pack_file) do
@@ -416,10 +395,9 @@ defmodule Pleroma.Emoji.Pack do
   end
 
   defp create_archive_and_cache(pack, hash) do
-    files = [~c"pack.json" | Enum.map(pack.files, fn {_, file} -> to_charlist(file) end)]
-
-    {:ok, {_, result}} =
-      :zip.zip(~c"#{pack.name}.zip", files, [:memory, cwd: to_charlist(pack.path)])
+    pack_file_list = Enum.into(pack.files, [], fn {_, f} -> f end)
+    files = ["pack.json" | pack_file_list]
+    {:ok, {_, result}} = SafeZip.zip("#{pack.name}.zip", files, pack.path, true)
 
     ttl_per_file = Pleroma.Config.get!([:emoji, :shared_pack_cache_seconds_per_file])
     overall_ttl = :timer.seconds(ttl_per_file * Enum.count(files))
@@ -478,7 +456,7 @@ defmodule Pleroma.Emoji.Pack do
   end
 
   defp save_file(%Plug.Upload{path: upload_path}, pack, filename) do
-    file_path = Path.join(pack.path, filename)
+    file_path = path_join_safe(pack.path, filename)
     create_subdirs(file_path)
 
     with {:ok, _} <- File.copy(upload_path, file_path) do
@@ -497,8 +475,8 @@ defmodule Pleroma.Emoji.Pack do
   end
 
   defp rename_file(pack, filename, new_filename) do
-    old_path = Path.join(pack.path, filename)
-    new_path = Path.join(pack.path, new_filename)
+    old_path = path_join_safe(pack.path, filename)
+    new_path = path_join_safe(pack.path, new_filename)
     create_subdirs(new_path)
 
     with :ok <- File.rename(old_path, new_path) do
@@ -516,7 +494,7 @@ defmodule Pleroma.Emoji.Pack do
 
   defp remove_file(pack, shortcode) do
     with {:ok, filename} <- get_filename(pack, shortcode),
-         emoji <- Path.join(pack.path, filename),
+         emoji <- path_join_safe(pack.path, filename),
          :ok <- File.rm(emoji) do
       remove_dir_if_empty(emoji, filename)
     end
@@ -534,7 +512,7 @@ defmodule Pleroma.Emoji.Pack do
 
   defp get_filename(pack, shortcode) do
     with %{^shortcode => filename} when is_binary(filename) <- pack.files,
-         file_path <- Path.join(pack.path, filename),
+         file_path <- path_join_safe(pack.path, filename),
          {:ok, _} <- File.stat(file_path) do
       {:ok, filename}
     else
@@ -584,11 +562,10 @@ defmodule Pleroma.Emoji.Pack do
 
   defp unzip(archive, pack_info, remote_pack, local_pack) do
     with :ok <- File.mkdir_p!(local_pack.path) do
-      files = Enum.map(remote_pack["files"], fn {_, path} -> to_charlist(path) end)
+      files = Enum.map(remote_pack["files"], fn {_, path} -> path end)
       # Fallback cannot contain a pack.json file
-      files = if pack_info[:fallback], do: files, else: [~c"pack.json" | files]
-
-      :zip.unzip(archive, cwd: to_charlist(local_pack.path), file_list: files)
+      files = if pack_info[:fallback], do: files, else: ["pack.json" | files]
+      SafeZip.unzip_data(archive, local_pack.path, files)
     end
   end
 
@@ -649,13 +626,43 @@ defmodule Pleroma.Emoji.Pack do
   end
 
   defp validate_has_all_files(pack, zip) do
-    with {:ok, f_list} <- :zip.unzip(zip, [:memory]) do
-      # Check if all files from the pack.json are in the archive
-      pack.files
-      |> Enum.all?(fn {_, from_manifest} ->
-        List.keyfind(f_list, to_charlist(from_manifest), 0)
+    # Check if all files from the pack.json are in the archive
+    eset =
+      Enum.reduce(pack.files, MapSet.new(), fn
+        {_, file}, s -> MapSet.put(s, to_charlist(file))
       end)
-      |> if(do: :ok, else: {:error, :incomplete})
+
+    if SafeZip.contains_all_data?(zip, eset),
+      do: :ok,
+      else: {:error, :incomplete}
+  end
+
+  defp path_join_name_safe(dir, name) do
+    if to_string(name) != Path.basename(name) or name in ["..", ".", ""] do
+      raise "Invalid or malicious pack name: #{name}"
+    else
+      Path.join(dir, name)
     end
   end
+
+  defp path_join_safe(dir, path) do
+    {:ok, safe_path} = Path.safe_relative(path)
+    Path.join(dir, safe_path)
+  end
+
+  defp map_zip_emojies(zip_files) do
+    Enum.reduce(zip_files, [], fn path, acc ->
+      with(
+        filename <- Path.basename(path),
+        shortcode <- Path.basename(filename, Path.extname(filename)),
+        # note: this only checks the shortcode, if an emoji already exists on the same path, but
+        #       with a different shortcode, the existing one will be degraded to an alias of the new
+        false <- Emoji.exist?(shortcode)
+      ) do
+        [%{path: path, filename: path, shortcode: shortcode} | acc]
+      else
+        _ -> acc
+      end
+    end)
+  end
 end
diff --git a/lib/pleroma/frontend.ex b/lib/pleroma/frontend.ex
index a4f427ae5..fe7f525ea 100644
--- a/lib/pleroma/frontend.ex
+++ b/lib/pleroma/frontend.ex
@@ -65,24 +65,12 @@ defmodule Pleroma.Frontend do
   end
 
   def unzip(zip, dest) do
-    with {:ok, unzipped} <- :zip.unzip(zip, [:memory]) do
-      File.rm_rf!(dest)
-      File.mkdir_p!(dest)
-
-      Enum.each(unzipped, fn {filename, data} ->
-        path = filename
-
-        new_file_path = Path.join(dest, path)
-
-        path
-        |> Path.dirname()
-        |> then(&Path.join(dest, &1))
-        |> File.mkdir_p!()
+    File.rm_rf!(dest)
+    File.mkdir_p!(dest)
 
-        if not File.dir?(new_file_path) do
-          File.write!(new_file_path, data)
-        end
-      end)
+    case Pleroma.SafeZip.unzip_data(zip, dest) do
+      {:ok, _} -> :ok
+      error -> error
     end
   end
 
diff --git a/lib/pleroma/hashtag.ex b/lib/pleroma/hashtag.ex
index a43d88220..3682f0c14 100644
--- a/lib/pleroma/hashtag.ex
+++ b/lib/pleroma/hashtag.ex
@@ -12,6 +12,7 @@ defmodule Pleroma.Hashtag do
   alias Pleroma.Hashtag
   alias Pleroma.Object
   alias Pleroma.Repo
+  alias Pleroma.User.HashtagFollow
 
   schema "hashtags" do
     field(:name, :string)
@@ -27,6 +28,14 @@ defmodule Pleroma.Hashtag do
     |> String.trim()
   end
 
+  def get_by_id(id) do
+    Repo.get(Hashtag, id)
+  end
+
+  def get_by_name(name) do
+    Repo.get_by(Hashtag, name: normalize_name(name))
+  end
+
   def get_or_create_by_name(name) do
     changeset = changeset(%Hashtag{}, %{name: name})
 
@@ -103,4 +112,22 @@ defmodule Pleroma.Hashtag do
       {:ok, deleted_count}
     end
   end
+
+  def get_followers(%Hashtag{id: hashtag_id}) do
+    from(hf in HashtagFollow)
+    |> where([hf], hf.hashtag_id == ^hashtag_id)
+    |> join(:inner, [hf], u in assoc(hf, :user))
+    |> select([hf, u], u.id)
+    |> Repo.all()
+  end
+
+  def get_recipients_for_activity(%Pleroma.Activity{object: %{hashtags: tags}})
+      when is_list(tags) do
+    tags
+    |> Enum.map(&get_followers/1)
+    |> List.flatten()
+    |> Enum.uniq()
+  end
+
+  def get_recipients_for_activity(_activity), do: []
 end
diff --git a/lib/pleroma/pagination.ex b/lib/pleroma/pagination.ex
index 8db732cc9..66812b17b 100644
--- a/lib/pleroma/pagination.ex
+++ b/lib/pleroma/pagination.ex
@@ -89,9 +89,9 @@ defmodule Pleroma.Pagination do
 
   defp cast_params(params) do
     param_types = %{
-      min_id: :string,
-      since_id: :string,
-      max_id: :string,
+      min_id: params[:id_type] || :string,
+      since_id: params[:id_type] || :string,
+      max_id: params[:id_type] || :string,
       offset: :integer,
       limit: :integer,
       skip_extra_order: :boolean,
diff --git a/lib/pleroma/safe_zip.ex b/lib/pleroma/safe_zip.ex
new file mode 100644
index 000000000..25fe434d6
--- /dev/null
+++ b/lib/pleroma/safe_zip.ex
@@ -0,0 +1,216 @@
+# Akkoma: Magically expressive social media
+# Copyright © 2024 Akkoma Authors <https://akkoma.dev/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.SafeZip do
+  @moduledoc """
+  Wraps the subset of Erlang's zip module we’d like to use
+  but enforces path-traversal safety everywhere and other checks.
+
+  For convenience almost all functions accept both elixir strings and charlists,
+  but output elixir strings themselves. However, this means the input parameter type
+  can no longer be used to distinguish archive file paths from archive binary data in memory,
+  thus where needed both a _data and _file variant are provided.
+  """
+
+  @type text() :: String.t() | [char()]
+
+  defp safe_path?(path) do
+    # Path accepts elixir’s chardata()
+    case Path.safe_relative(path) do
+      {:ok, _} -> true
+      _ -> false
+    end
+  end
+
+  defp safe_type?(file_type) do
+    if file_type in [:regular, :directory] do
+      true
+    else
+      false
+    end
+  end
+
+  defp maybe_add_file(_type, _path_charlist, nil), do: nil
+
+  defp maybe_add_file(:regular, path_charlist, file_list),
+    do: [to_string(path_charlist) | file_list]
+
+  defp maybe_add_file(_type, _path_charlist, file_list), do: file_list
+
+  @spec check_safe_archive_and_maybe_list_files(binary() | [char()], [term()], boolean()) ::
+          {:ok, [String.t()]} | {:error, reason :: term()}
+  defp check_safe_archive_and_maybe_list_files(archive, opts, list) do
+    acc = if list, do: [], else: nil
+
+    with {:ok, table} <- :zip.table(archive, opts) do
+      Enum.reduce_while(table, {:ok, acc}, fn
+        # ZIP comment
+        {:zip_comment, _}, acc ->
+          {:cont, acc}
+
+        # File entry
+        {:zip_file, path, info, _comment, _offset, _comp_size}, {:ok, fl} ->
+          with {_, type} <- {:get_type, elem(info, 2)},
+               {_, true} <- {:type, safe_type?(type)},
+               {_, true} <- {:safe_path, safe_path?(path)} do
+            {:cont, {:ok, maybe_add_file(type, path, fl)}}
+          else
+            {:get_type, e} ->
+              {:halt,
+               {:error, "Couldn't determine file type of ZIP entry at #{path} (#{inspect(e)})"}}
+
+            {:type, _} ->
+              {:halt, {:error, "Potentially unsafe file type in ZIP at: #{path}"}}
+
+            {:safe_path, _} ->
+              {:halt, {:error, "Unsafe path in ZIP: #{path}"}}
+          end
+
+        # new OTP version?
+        _, _acc ->
+          {:halt, {:error, "Unknown ZIP record type"}}
+      end)
+    end
+  end
+
+  @spec check_safe_archive_and_list_files(binary() | [char()], [term()]) ::
+          {:ok, [String.t()]} | {:error, reason :: term()}
+  defp check_safe_archive_and_list_files(archive, opts \\ []) do
+    check_safe_archive_and_maybe_list_files(archive, opts, true)
+  end
+
+  @spec check_safe_archive(binary() | [char()], [term()]) :: :ok | {:error, reason :: term()}
+  defp check_safe_archive(archive, opts \\ []) do
+    case check_safe_archive_and_maybe_list_files(archive, opts, false) do
+      {:ok, _} -> :ok
+      error -> error
+    end
+  end
+
+  @spec check_safe_file_list([text()], text()) :: :ok | {:error, term()}
+  defp check_safe_file_list([], _), do: :ok
+
+  defp check_safe_file_list([path | tail], cwd) do
+    with {_, true} <- {:path, safe_path?(path)},
+         {_, {:ok, fstat}} <- {:stat, File.stat(Path.expand(path, cwd))},
+         {_, true} <- {:type, safe_type?(fstat.type)} do
+      check_safe_file_list(tail, cwd)
+    else
+      {:path, _} ->
+        {:error, "Unsafe path escaping cwd: #{path}"}
+
+      {:stat, e} ->
+        {:error, "Unable to check file type of #{path}: #{inspect(e)}"}
+
+      {:type, _} ->
+        {:error, "Unsafe type at #{path}"}
+    end
+  end
+
+  defp check_safe_file_list(_, _), do: {:error, "Malformed file_list"}
+
+  @doc """
+  Checks whether the archive data contais file entries for all paths from fset
+
+  Note this really only accepts entries corresponding to regular _files_,
+  if a path is contained as for example an directory, this does not count as a match.
+  """
+  @spec contains_all_data?(binary(), MapSet.t()) :: true | false
+  def contains_all_data?(archive_data, fset) do
+    with {:ok, table} <- :zip.table(archive_data) do
+      remaining =
+        Enum.reduce(table, fset, fn
+          {:zip_file, path, info, _comment, _offset, _comp_size}, fset ->
+            if elem(info, 2) == :regular do
+              MapSet.delete(fset, path)
+            else
+              fset
+            end
+
+          _, _ ->
+            fset
+        end)
+        |> MapSet.size()
+
+      if remaining == 0, do: true, else: false
+    else
+      _ -> false
+    end
+  end
+
+  @doc """
+  List all file entries in ZIP, or error if invalid or unsafe.
+
+  Note this really only lists regular files, no directories, ZIP comments or other types!
+  """
+  @spec list_dir_file(text()) :: {:ok, [String.t()]} | {:error, reason :: term()}
+  def list_dir_file(archive) do
+    path = to_charlist(archive)
+    check_safe_archive_and_list_files(path)
+  end
+
+  defp stringify_zip({:ok, {fname, data}}), do: {:ok, {to_string(fname), data}}
+  defp stringify_zip({:ok, fname}), do: {:ok, to_string(fname)}
+  defp stringify_zip(ret), do: ret
+
+  @spec zip(text(), text(), [text()], boolean()) ::
+          {:ok, file_name :: String.t()}
+          | {:ok, {file_name :: String.t(), file_data :: binary()}}
+          | {:error, reason :: term()}
+  def zip(name, file_list, cwd, memory \\ false) do
+    opts = [{:cwd, to_charlist(cwd)}]
+    opts = if memory, do: [:memory | opts], else: opts
+
+    with :ok <- check_safe_file_list(file_list, cwd) do
+      file_list = for f <- file_list, do: to_charlist(f)
+      name = to_charlist(name)
+      stringify_zip(:zip.zip(name, file_list, opts))
+    end
+  end
+
+  @spec unzip_file(text(), text(), [text()] | nil) ::
+          {:ok, [String.t()]}
+          | {:error, reason :: term()}
+          | {:error, {name :: text(), reason :: term()}}
+  def unzip_file(archive, target_dir, file_list \\ nil) do
+    do_unzip(to_charlist(archive), to_charlist(target_dir), file_list)
+  end
+
+  @spec unzip_data(binary(), text(), [text()] | nil) ::
+          {:ok, [String.t()]}
+          | {:error, reason :: term()}
+          | {:error, {name :: text(), reason :: term()}}
+  def unzip_data(archive, target_dir, file_list \\ nil) do
+    do_unzip(archive, to_charlist(target_dir), file_list)
+  end
+
+  defp stringify_unzip({:ok, [{_fname, _data} | _] = filebinlist}),
+    do: {:ok, Enum.map(filebinlist, fn {fname, data} -> {to_string(fname), data} end)}
+
+  defp stringify_unzip({:ok, [_fname | _] = filelist}),
+    do: {:ok, Enum.map(filelist, fn fname -> to_string(fname) end)}
+
+  defp stringify_unzip({:error, {fname, term}}), do: {:error, {to_string(fname), term}}
+  defp stringify_unzip(ret), do: ret
+
+  @spec do_unzip(binary() | [char()], text(), [text()] | nil) ::
+          {:ok, [String.t()]}
+          | {:error, reason :: term()}
+          | {:error, {name :: text(), reason :: term()}}
+  defp do_unzip(archive, target_dir, file_list) do
+    opts =
+      if file_list != nil do
+        [
+          file_list: for(f <- file_list, do: to_charlist(f)),
+          cwd: target_dir
+        ]
+      else
+        [cwd: target_dir]
+      end
+
+    with :ok <- check_safe_archive(archive) do
+      stringify_unzip(:zip.unzip(archive, opts))
+    end
+  end
+end
diff --git a/lib/pleroma/upload/filter/analyze_metadata.ex b/lib/pleroma/upload/filter/analyze_metadata.ex
index 7ee643277..a8480bf36 100644
--- a/lib/pleroma/upload/filter/analyze_metadata.ex
+++ b/lib/pleroma/upload/filter/analyze_metadata.ex
@@ -90,9 +90,13 @@ defmodule Pleroma.Upload.Filter.AnalyzeMetadata do
       {:ok, rgb} =
         if Image.has_alpha?(resized_image) do
           # remove alpha channel
-          resized_image
-          |> Operation.extract_band!(0, n: 3)
-          |> Image.write_to_binary()
+          case Operation.extract_band(resized_image, 0, n: 3) do
+            {:ok, data} ->
+              Image.write_to_binary(data)
+
+            _ ->
+              Image.write_to_binary(resized_image)
+          end
         else
           Image.write_to_binary(resized_image)
         end
diff --git a/lib/pleroma/user.ex b/lib/pleroma/user.ex
index 7a36ece77..d9da9ede1 100644
--- a/lib/pleroma/user.ex
+++ b/lib/pleroma/user.ex
@@ -19,6 +19,7 @@ defmodule Pleroma.User do
   alias Pleroma.Emoji
   alias Pleroma.FollowingRelationship
   alias Pleroma.Formatter
+  alias Pleroma.Hashtag
   alias Pleroma.HTML
   alias Pleroma.Keys
   alias Pleroma.MFA
@@ -27,6 +28,7 @@ defmodule Pleroma.User do
   alias Pleroma.Registration
   alias Pleroma.Repo
   alias Pleroma.User
+  alias Pleroma.User.HashtagFollow
   alias Pleroma.UserRelationship
   alias Pleroma.Web.ActivityPub.ActivityPub
   alias Pleroma.Web.ActivityPub.Builder
@@ -174,6 +176,12 @@ defmodule Pleroma.User do
     has_many(:outgoing_relationships, UserRelationship, foreign_key: :source_id)
     has_many(:incoming_relationships, UserRelationship, foreign_key: :target_id)
 
+    many_to_many(:followed_hashtags, Hashtag,
+      on_replace: :delete,
+      on_delete: :delete_all,
+      join_through: HashtagFollow
+    )
+
     for {relationship_type,
          [
            {outgoing_relation, outgoing_relation_target},
@@ -2861,4 +2869,54 @@ defmodule Pleroma.User do
       birthday_month: month
     })
   end
+
+  defp maybe_load_followed_hashtags(%User{followed_hashtags: follows} = user)
+       when is_list(follows),
+       do: user
+
+  defp maybe_load_followed_hashtags(%User{} = user) do
+    followed_hashtags = HashtagFollow.get_by_user(user)
+    %{user | followed_hashtags: followed_hashtags}
+  end
+
+  def followed_hashtags(%User{followed_hashtags: follows})
+      when is_list(follows),
+      do: follows
+
+  def followed_hashtags(%User{} = user) do
+    {:ok, user} =
+      user
+      |> maybe_load_followed_hashtags()
+      |> set_cache()
+
+    user.followed_hashtags
+  end
+
+  def follow_hashtag(%User{} = user, %Hashtag{} = hashtag) do
+    Logger.debug("Follow hashtag #{hashtag.name} for user #{user.nickname}")
+    user = maybe_load_followed_hashtags(user)
+
+    with {:ok, _} <- HashtagFollow.new(user, hashtag),
+         follows <- HashtagFollow.get_by_user(user),
+         %User{} = user <- user |> Map.put(:followed_hashtags, follows) do
+      user
+      |> set_cache()
+    end
+  end
+
+  def unfollow_hashtag(%User{} = user, %Hashtag{} = hashtag) do
+    Logger.debug("Unfollow hashtag #{hashtag.name} for user #{user.nickname}")
+    user = maybe_load_followed_hashtags(user)
+
+    with {:ok, _} <- HashtagFollow.delete(user, hashtag),
+         follows <- HashtagFollow.get_by_user(user),
+         %User{} = user <- user |> Map.put(:followed_hashtags, follows) do
+      user
+      |> set_cache()
+    end
+  end
+
+  def following_hashtag?(%User{} = user, %Hashtag{} = hashtag) do
+    not is_nil(HashtagFollow.get(user, hashtag))
+  end
 end
diff --git a/lib/pleroma/user/backup.ex b/lib/pleroma/user/backup.ex
index d77d49890..244b08adb 100644
--- a/lib/pleroma/user/backup.ex
+++ b/lib/pleroma/user/backup.ex
@@ -16,6 +16,7 @@ defmodule Pleroma.User.Backup do
   alias Pleroma.Bookmark
   alias Pleroma.Config
   alias Pleroma.Repo
+  alias Pleroma.SafeZip
   alias Pleroma.Uploaders.Uploader
   alias Pleroma.User
   alias Pleroma.Web.ActivityPub.ActivityPub
@@ -179,12 +180,12 @@ defmodule Pleroma.User.Backup do
   end
 
   @files [
-    ~c"actor.json",
-    ~c"outbox.json",
-    ~c"likes.json",
-    ~c"bookmarks.json",
-    ~c"followers.json",
-    ~c"following.json"
+    "actor.json",
+    "outbox.json",
+    "likes.json",
+    "bookmarks.json",
+    "followers.json",
+    "following.json"
   ]
 
   @spec run(t()) :: {:ok, t()} | {:error, :failed}
@@ -200,7 +201,7 @@ defmodule Pleroma.User.Backup do
          {_, :ok} <- {:followers, followers(backup.tempdir, backup.user)},
          {_, :ok} <- {:following, following(backup.tempdir, backup.user)},
          {_, {:ok, _zip_path}} <-
-           {:zip, :zip.create(to_charlist(tempfile), @files, cwd: to_charlist(backup.tempdir))},
+           {:zip, SafeZip.zip(tempfile, @files, backup.tempdir)},
          {_, {:ok, %File.Stat{size: zip_size}}} <- {:filestat, File.stat(tempfile)},
          {:ok, updated_backup} <- update_record(backup, %{file_size: zip_size}) do
       {:ok, updated_backup}
@@ -246,7 +247,13 @@ defmodule Pleroma.User.Backup do
   defp actor(dir, user) do
     with {:ok, json} <-
            UserView.render("user.json", %{user: user})
-           |> Map.merge(%{"likes" => "likes.json", "bookmarks" => "bookmarks.json"})
+           |> Map.merge(%{
+             "bookmarks" => "bookmarks.json",
+             "likes" => "likes.json",
+             "outbox" => "outbox.json",
+             "followers" => "followers.json",
+             "following" => "following.json"
+           })
            |> Jason.encode() do
       File.write(Path.join(dir, "actor.json"), json)
     end
diff --git a/lib/pleroma/user/hashtag_follow.ex b/lib/pleroma/user/hashtag_follow.ex
new file mode 100644
index 000000000..3e28b130b
--- /dev/null
+++ b/lib/pleroma/user/hashtag_follow.ex
@@ -0,0 +1,55 @@
+defmodule Pleroma.User.HashtagFollow do
+  use Ecto.Schema
+  import Ecto.Query
+  import Ecto.Changeset
+
+  alias Pleroma.Hashtag
+  alias Pleroma.Repo
+  alias Pleroma.User
+
+  schema "user_follows_hashtag" do
+    belongs_to(:user, User, type: FlakeId.Ecto.CompatType)
+    belongs_to(:hashtag, Hashtag)
+  end
+
+  def changeset(%__MODULE__{} = user_hashtag_follow, attrs) do
+    user_hashtag_follow
+    |> cast(attrs, [:user_id, :hashtag_id])
+    |> unique_constraint(:hashtag_id,
+      name: :user_hashtag_follows_user_id_hashtag_id_index,
+      message: "already following"
+    )
+    |> validate_required([:user_id, :hashtag_id])
+  end
+
+  def new(%User{} = user, %Hashtag{} = hashtag) do
+    %__MODULE__{}
+    |> changeset(%{user_id: user.id, hashtag_id: hashtag.id})
+    |> Repo.insert(on_conflict: :nothing)
+  end
+
+  def delete(%User{} = user, %Hashtag{} = hashtag) do
+    with %__MODULE__{} = user_hashtag_follow <- get(user, hashtag) do
+      Repo.delete(user_hashtag_follow)
+    else
+      _ -> {:ok, nil}
+    end
+  end
+
+  def get(%User{} = user, %Hashtag{} = hashtag) do
+    from(hf in __MODULE__)
+    |> where([hf], hf.user_id == ^user.id and hf.hashtag_id == ^hashtag.id)
+    |> Repo.one()
+  end
+
+  def get_by_user(%User{} = user) do
+    user
+    |> followed_hashtags_query()
+    |> Repo.all()
+  end
+
+  def followed_hashtags_query(%User{} = user) do
+    Ecto.assoc(user, :followed_hashtags)
+    |> Ecto.Query.order_by([h], desc: h.id)
+  end
+end
diff --git a/lib/pleroma/web/activity_pub/activity_pub.ex b/lib/pleroma/web/activity_pub/activity_pub.ex
index df8795fe4..62c7a7b31 100644
--- a/lib/pleroma/web/activity_pub/activity_pub.ex
+++ b/lib/pleroma/web/activity_pub/activity_pub.ex
@@ -924,6 +924,31 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
     )
   end
 
+  # Essentially, either look for activities addressed to `recipients`, _OR_ ones
+  # that reference a hashtag that the user follows
+  # Firstly, two fallbacks in case there's no hashtag constraint, or the user doesn't
+  # follow any
+  defp restrict_recipients_or_hashtags(query, recipients, user, nil) do
+    restrict_recipients(query, recipients, user)
+  end
+
+  defp restrict_recipients_or_hashtags(query, recipients, user, []) do
+    restrict_recipients(query, recipients, user)
+  end
+
+  defp restrict_recipients_or_hashtags(query, recipients, _user, hashtag_ids) do
+    from([activity, object] in query)
+    |> join(:left, [activity, object], hto in "hashtags_objects",
+      on: hto.object_id == object.id,
+      as: :hto
+    )
+    |> where(
+      [activity, object, hto: hto],
+      (hto.hashtag_id in ^hashtag_ids and ^Constants.as_public() in activity.recipients) or
+        fragment("? && ?", ^recipients, activity.recipients)
+    )
+  end
+
   defp restrict_local(query, %{local_only: true}) do
     from(activity in query, where: activity.local == true)
   end
@@ -1414,7 +1439,7 @@ defmodule Pleroma.Web.ActivityPub.ActivityPub do
       |> maybe_preload_report_notes(opts)
       |> maybe_set_thread_muted_field(opts)
       |> maybe_order(opts)
-      |> restrict_recipients(recipients, opts[:user])
+      |> restrict_recipients_or_hashtags(recipients, opts[:user], opts[:followed_hashtags])
       |> restrict_replies(opts)
       |> restrict_since(opts)
       |> restrict_local(opts)
diff --git a/lib/pleroma/web/activity_pub/mrf/dnsrbl_policy.ex b/lib/pleroma/web/activity_pub/mrf/dnsrbl_policy.ex
deleted file mode 100644
index ca41c464c..000000000
--- a/lib/pleroma/web/activity_pub/mrf/dnsrbl_policy.ex
+++ /dev/null
@@ -1,146 +0,0 @@
-# Pleroma: A lightweight social networking server
-# Copyright © 2017-2024 Pleroma Authors <https://pleroma.social/>
-# SPDX-License-Identifier: AGPL-3.0-only
-
-defmodule Pleroma.Web.ActivityPub.MRF.DNSRBLPolicy do
-  @moduledoc """
-  Dynamic activity filtering based on an RBL database
-
-  This MRF makes queries to a custom DNS server which will
-  respond with values indicating the classification of the domain
-  the activity originated from. This method has been widely used
-  in the email anti-spam industry for very fast reputation checks.
-
-  e.g., if the DNS response is 127.0.0.1 or empty, the domain is OK
-  Other values such as 127.0.0.2 may be used for specific classifications.
-
-  Information for why the host is blocked can be stored in a corresponding TXT record.
-
-  This method is fail-open so if the queries fail the activites are accepted.
-
-  An example of software meant for this purpsoe is rbldnsd which can be found
-  at http://www.corpit.ru/mjt/rbldnsd.html or mirrored at
-  https://git.pleroma.social/feld/rbldnsd
-
-  It is highly recommended that you run your own copy of rbldnsd and use an
-  external mechanism to sync/share the contents of the zone file. This is
-  important to keep the latency on the queries as low as possible and prevent
-  your DNS server from being attacked so it fails and content is permitted.
-  """
-
-  @behaviour Pleroma.Web.ActivityPub.MRF.Policy
-
-  alias Pleroma.Config
-
-  require Logger
-
-  @query_retries 1
-  @query_timeout 500
-
-  @impl true
-  def filter(%{"actor" => actor} = activity) do
-    actor_info = URI.parse(actor)
-
-    with {:ok, activity} <- check_rbl(actor_info, activity) do
-      {:ok, activity}
-    else
-      _ -> {:reject, "[DNSRBLPolicy]"}
-    end
-  end
-
-  @impl true
-  def filter(activity), do: {:ok, activity}
-
-  @impl true
-  def describe do
-    mrf_dnsrbl =
-      Config.get(:mrf_dnsrbl)
-      |> Enum.into(%{})
-
-    {:ok, %{mrf_dnsrbl: mrf_dnsrbl}}
-  end
-
-  @impl true
-  def config_description do
-    %{
-      key: :mrf_dnsrbl,
-      related_policy: "Pleroma.Web.ActivityPub.MRF.DNSRBLPolicy",
-      label: "MRF DNSRBL",
-      description: "DNS RealTime Blackhole Policy",
-      children: [
-        %{
-          key: :nameserver,
-          type: {:string},
-          description: "DNSRBL Nameserver to Query (IP or hostame)",
-          suggestions: ["127.0.0.1"]
-        },
-        %{
-          key: :port,
-          type: {:string},
-          description: "Nameserver port",
-          suggestions: ["53"]
-        },
-        %{
-          key: :zone,
-          type: {:string},
-          description: "Root zone for querying",
-          suggestions: ["bl.pleroma.com"]
-        }
-      ]
-    }
-  end
-
-  defp check_rbl(%{host: actor_host}, activity) do
-    with false <- match?(^actor_host, Pleroma.Web.Endpoint.host()),
-         zone when not is_nil(zone) <- Keyword.get(Config.get([:mrf_dnsrbl]), :zone) do
-      query =
-        Enum.join([actor_host, zone], ".")
-        |> String.to_charlist()
-
-      rbl_response = rblquery(query)
-
-      if Enum.empty?(rbl_response) do
-        {:ok, activity}
-      else
-        Task.start(fn ->
-          reason =
-            case rblquery(query, :txt) do
-              [[result]] -> result
-              _ -> "undefined"
-            end
-
-          Logger.warning(
-            "DNSRBL Rejected activity from #{actor_host} for reason: #{inspect(reason)}"
-          )
-        end)
-
-        :error
-      end
-    else
-      _ -> {:ok, activity}
-    end
-  end
-
-  defp get_rblhost_ip(rblhost) do
-    case rblhost |> String.to_charlist() |> :inet_parse.address() do
-      {:ok, _} -> rblhost |> String.to_charlist() |> :inet_parse.address()
-      _ -> {:ok, rblhost |> String.to_charlist() |> :inet_res.lookup(:in, :a) |> Enum.random()}
-    end
-  end
-
-  defp rblquery(query, type \\ :a) do
-    config = Config.get([:mrf_dnsrbl])
-
-    case get_rblhost_ip(config[:nameserver]) do
-      {:ok, rblnsip} ->
-        :inet_res.lookup(query, :in, type,
-          nameservers: [{rblnsip, config[:port]}],
-          timeout: @query_timeout,
-          retry: @query_retries
-        )
-
-      _ ->
-        []
-    end
-  end
-end
diff --git a/lib/pleroma/web/activity_pub/mrf/fo_direct_reply.ex b/lib/pleroma/web/activity_pub/mrf/fo_direct_reply.ex
deleted file mode 100644
index 2cf22745a..000000000
--- a/lib/pleroma/web/activity_pub/mrf/fo_direct_reply.ex
+++ /dev/null
@@ -1,53 +0,0 @@
-# Pleroma: A lightweight social networking server
-# Copyright © 2017-2024 Pleroma Authors <https://pleroma.social/>
-# SPDX-License-Identifier: AGPL-3.0-only
-
-defmodule Pleroma.Web.ActivityPub.MRF.FODirectReply do
-  @moduledoc """
-  FODirectReply alters the scope of replies to activities which are Followers Only to be Direct. The purpose of this policy is to prevent broken threads for followers of the reply author because their response was to a user that they are not also following.
-  """
-
-  alias Pleroma.Object
-  alias Pleroma.User
-  alias Pleroma.Web.ActivityPub.Visibility
-
-  @behaviour Pleroma.Web.ActivityPub.MRF.Policy
-
-  @impl true
-  def filter(
-        %{
-          "type" => "Create",
-          "to" => to,
-          "object" => %{
-            "actor" => actor,
-            "type" => "Note",
-            "inReplyTo" => in_reply_to
-          }
-        } = activity
-      ) do
-    with true <- is_binary(in_reply_to),
-         %User{follower_address: followers_collection, local: true} <- User.get_by_ap_id(actor),
-         %Object{} = in_reply_to_object <- Object.get_by_ap_id(in_reply_to),
-         "private" <- Visibility.get_visibility(in_reply_to_object) do
-      direct_to = to -- [followers_collection]
-
-      updated_activity =
-        activity
-        |> Map.put("cc", [])
-        |> Map.put("to", direct_to)
-        |> Map.put("directMessage", true)
-        |> put_in(["object", "cc"], [])
-        |> put_in(["object", "to"], direct_to)
-
-      {:ok, updated_activity}
-    else
-      _ -> {:ok, activity}
-    end
-  end
-
-  @impl true
-  def filter(activity), do: {:ok, activity}
-
-  @impl true
-  def describe, do: {:ok, %{}}
-end
diff --git a/lib/pleroma/web/activity_pub/mrf/quiet_reply.ex b/lib/pleroma/web/activity_pub/mrf/quiet_reply.ex
deleted file mode 100644
index b07dc3b56..000000000
--- a/lib/pleroma/web/activity_pub/mrf/quiet_reply.ex
+++ /dev/null
@@ -1,60 +0,0 @@
-# Pleroma: A lightweight social networking server
-# Copyright © 2017-2023 Pleroma Authors <https://pleroma.social/>
-# SPDX-License-Identifier: AGPL-3.0-only
-
-defmodule Pleroma.Web.ActivityPub.MRF.QuietReply do
-  @moduledoc """
-  QuietReply alters the scope of activities from local users when replying by enforcing them to be "Unlisted" or "Quiet Public". This delivers the activity to all the expected recipients and instances, but it will not be published in the Federated / The Whole Known Network timelines. It will still be published to the Home timelines of the user's followers and visible to anyone who opens the thread.
-  """
-  require Pleroma.Constants
-
-  alias Pleroma.User
-
-  @behaviour Pleroma.Web.ActivityPub.MRF.Policy
-
-  @impl true
-  def history_awareness, do: :auto
-
-  @impl true
-  def filter(
-        %{
-          "type" => "Create",
-          "to" => to,
-          "cc" => cc,
-          "object" => %{
-            "actor" => actor,
-            "type" => "Note",
-            "inReplyTo" => in_reply_to
-          }
-        } = activity
-      ) do
-    with true <- is_binary(in_reply_to),
-         false <- match?([], cc),
-         %User{follower_address: followers_collection, local: true} <-
-           User.get_by_ap_id(actor) do
-      updated_to =
-        to
-        |> Kernel.++([followers_collection])
-        |> Kernel.--([Pleroma.Constants.as_public()])
-
-      updated_cc = [Pleroma.Constants.as_public()]
-
-      updated_activity =
-        activity
-        |> Map.put("to", updated_to)
-        |> Map.put("cc", updated_cc)
-        |> put_in(["object", "to"], updated_to)
-        |> put_in(["object", "cc"], updated_cc)
-
-      {:ok, updated_activity}
-    else
-      _ -> {:ok, activity}
-    end
-  end
-
-  @impl true
-  def filter(activity), do: {:ok, activity}
-
-  @impl true
-  def describe, do: {:ok, %{}}
-end
diff --git a/lib/pleroma/web/activity_pub/object_validator.ex b/lib/pleroma/web/activity_pub/object_validator.ex
index c509890f6..ee12f3ebf 100644
--- a/lib/pleroma/web/activity_pub/object_validator.ex
+++ b/lib/pleroma/web/activity_pub/object_validator.ex
@@ -26,6 +26,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidator do
   alias Pleroma.Web.ActivityPub.ObjectValidators.AudioImageVideoValidator
   alias Pleroma.Web.ActivityPub.ObjectValidators.BlockValidator
   alias Pleroma.Web.ActivityPub.ObjectValidators.ChatMessageValidator
+  alias Pleroma.Web.ActivityPub.ObjectValidators.CommonFixes
   alias Pleroma.Web.ActivityPub.ObjectValidators.CreateChatMessageValidator
   alias Pleroma.Web.ActivityPub.ObjectValidators.CreateGenericValidator
   alias Pleroma.Web.ActivityPub.ObjectValidators.DeleteValidator
@@ -115,7 +116,10 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidator do
         meta
       )
       when objtype in ~w[Question Answer Audio Video Image Event Article Note Page] do
-    with {:ok, object_data} <- cast_and_apply_and_stringify_with_history(object),
+    with {:ok, object_data} <-
+           object
+           |> CommonFixes.maybe_add_language_from_activity(create_activity)
+           |> cast_and_apply_and_stringify_with_history(),
          meta = Keyword.put(meta, :object_data, object_data),
          {:ok, create_activity} <-
            create_activity
@@ -165,7 +169,11 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidator do
       )
       when objtype in ~w[Question Answer Audio Video Event Article Note Page] do
     with {_, false} <- {:local, Access.get(meta, :local, false)},
-         {_, {:ok, object_data, _}} <- {:object_validation, validate(object, meta)},
+         {_, {:ok, object_data, _}} <-
+           {:object_validation,
+            object
+            |> CommonFixes.maybe_add_language_from_activity(update_activity)
+            |> validate(meta)},
          meta = Keyword.put(meta, :object_data, object_data),
          {:ok, update_activity} <-
            update_activity
diff --git a/lib/pleroma/web/activity_pub/object_validators/article_note_page_validator.ex b/lib/pleroma/web/activity_pub/object_validators/article_note_page_validator.ex
index 1b5b2e8fb..81ab354fe 100644
--- a/lib/pleroma/web/activity_pub/object_validators/article_note_page_validator.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/article_note_page_validator.ex
@@ -30,7 +30,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.ArticleNotePageValidator do
 
   def cast_and_apply(data) do
     data
-    |> cast_data
+    |> cast_data()
     |> apply_action(:insert)
   end
 
@@ -85,8 +85,11 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.ArticleNotePageValidator do
     |> fix_replies()
     |> fix_attachments()
     |> CommonFixes.fix_quote_url()
+    |> CommonFixes.fix_likes()
     |> Transmogrifier.fix_emoji()
     |> Transmogrifier.fix_content_map()
+    |> CommonFixes.maybe_add_language()
+    |> CommonFixes.maybe_add_content_map()
   end
 
   def changeset(struct, data) do
diff --git a/lib/pleroma/web/activity_pub/object_validators/audio_image_video_validator.ex b/lib/pleroma/web/activity_pub/object_validators/audio_image_video_validator.ex
index 65ac6bb93..034c6f33f 100644
--- a/lib/pleroma/web/activity_pub/object_validators/audio_image_video_validator.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/audio_image_video_validator.ex
@@ -100,6 +100,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.AudioImageVideoValidator do
     |> CommonFixes.fix_actor()
     |> CommonFixes.fix_object_defaults()
     |> CommonFixes.fix_quote_url()
+    |> CommonFixes.fix_likes()
     |> Transmogrifier.fix_emoji()
     |> fix_url()
     |> fix_content()
diff --git a/lib/pleroma/web/activity_pub/object_validators/common_fields.ex b/lib/pleroma/web/activity_pub/object_validators/common_fields.ex
index 1a5d02601..22cf0cc05 100644
--- a/lib/pleroma/web/activity_pub/object_validators/common_fields.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/common_fields.ex
@@ -31,6 +31,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonFields do
   defmacro object_fields do
     quote bind_quoted: binding() do
       field(:content, :string)
+      field(:contentMap, ObjectValidators.ContentLanguageMap)
 
       field(:published, ObjectValidators.DateTime)
       field(:updated, ObjectValidators.DateTime)
@@ -58,6 +59,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonFields do
       field(:like_count, :integer, default: 0)
       field(:announcement_count, :integer, default: 0)
       field(:quotes_count, :integer, default: 0)
+      field(:language, ObjectValidators.LanguageCode)
       field(:inReplyTo, ObjectValidators.ObjectID)
       field(:quoteUrl, ObjectValidators.ObjectID)
       field(:url, ObjectValidators.BareUri)
diff --git a/lib/pleroma/web/activity_pub/object_validators/common_fixes.ex b/lib/pleroma/web/activity_pub/object_validators/common_fixes.ex
index 4699029d4..87d3e0c8f 100644
--- a/lib/pleroma/web/activity_pub/object_validators/common_fixes.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/common_fixes.ex
@@ -11,6 +11,11 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonFixes do
   alias Pleroma.Web.ActivityPub.Transmogrifier
   alias Pleroma.Web.ActivityPub.Utils
 
+  import Pleroma.EctoType.ActivityPub.ObjectValidators.LanguageCode,
+    only: [good_locale_code?: 1]
+
+  import Pleroma.Web.Utils.Guards, only: [not_empty_string: 1]
+
   require Pleroma.Constants
 
   def cast_and_filter_recipients(message, field, follower_collection, field_fallback \\ []) do
@@ -114,6 +119,13 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonFixes do
 
   def fix_quote_url(data), do: data
 
+  # On Mastodon, `"likes"` attribute includes an inlined `Collection` with `totalItems`,
+  # not a list of users.
+  # https://github.com/mastodon/mastodon/pull/32007
+  def fix_likes(%{"likes" => %{}} = data), do: Map.drop(data, ["likes"])
+
+  def fix_likes(data), do: data
+
   # https://codeberg.org/fediverse/fep/src/branch/main/fep/e232/fep-e232.md
   def object_link_tag?(%{
         "type" => "Link",
@@ -125,4 +137,60 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.CommonFixes do
   end
 
   def object_link_tag?(_), do: false
+
+  def maybe_add_language_from_activity(object, activity) do
+    language = get_language_from_context(activity)
+
+    if language do
+      Map.put(object, "language", language)
+    else
+      object
+    end
+  end
+
+  def maybe_add_language(object) do
+    language =
+      [
+        get_language_from_context(object),
+        get_language_from_content_map(object)
+      ]
+      |> Enum.find(&good_locale_code?(&1))
+
+    if language do
+      Map.put(object, "language", language)
+    else
+      object
+    end
+  end
+
+  defp get_language_from_context(%{"@context" => context}) when is_list(context) do
+    case context
+         |> Enum.find(fn
+           %{"@language" => language} -> language != "und"
+           _ -> nil
+         end) do
+      %{"@language" => language} -> language
+      _ -> nil
+    end
+  end
+
+  defp get_language_from_context(_), do: nil
+
+  defp get_language_from_content_map(%{"contentMap" => content_map, "content" => source_content}) do
+    content_groups = Map.to_list(content_map)
+
+    case Enum.find(content_groups, fn {_, content} -> content == source_content end) do
+      {language, _} -> language
+      _ -> nil
+    end
+  end
+
+  defp get_language_from_content_map(_), do: nil
+
+  def maybe_add_content_map(%{"language" => language, "content" => content} = object)
+      when not_empty_string(language) do
+    Map.put(object, "contentMap", Map.put(%{}, language, content))
+  end
+
+  def maybe_add_content_map(object), do: object
 end
diff --git a/lib/pleroma/web/activity_pub/object_validators/event_validator.ex b/lib/pleroma/web/activity_pub/object_validators/event_validator.ex
index ab204f69a..ea14d6aca 100644
--- a/lib/pleroma/web/activity_pub/object_validators/event_validator.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/event_validator.ex
@@ -28,7 +28,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.EventValidator do
 
   def cast_and_apply(data) do
     data
-    |> cast_data
+    |> cast_data()
     |> apply_action(:insert)
   end
 
@@ -38,6 +38,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.EventValidator do
     |> validate_data()
   end
 
+  @spec cast_data(map()) :: map()
   def cast_data(data) do
     %__MODULE__{}
     |> changeset(data)
@@ -47,7 +48,10 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.EventValidator do
     data
     |> CommonFixes.fix_actor()
     |> CommonFixes.fix_object_defaults()
+    |> CommonFixes.fix_likes()
     |> Transmogrifier.fix_emoji()
+    |> CommonFixes.maybe_add_language()
+    |> CommonFixes.maybe_add_content_map()
   end
 
   def changeset(struct, data) do
diff --git a/lib/pleroma/web/activity_pub/object_validators/question_validator.ex b/lib/pleroma/web/activity_pub/object_validators/question_validator.ex
index 7f9d4d648..21940f4f1 100644
--- a/lib/pleroma/web/activity_pub/object_validators/question_validator.ex
+++ b/lib/pleroma/web/activity_pub/object_validators/question_validator.ex
@@ -64,6 +64,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.QuestionValidator do
     |> CommonFixes.fix_actor()
     |> CommonFixes.fix_object_defaults()
     |> CommonFixes.fix_quote_url()
+    |> CommonFixes.fix_likes()
     |> Transmogrifier.fix_emoji()
     |> fix_closed()
   end
diff --git a/lib/pleroma/web/activity_pub/transmogrifier.ex b/lib/pleroma/web/activity_pub/transmogrifier.ex
index 2f8a7f8f2..1e6ee7dc8 100644
--- a/lib/pleroma/web/activity_pub/transmogrifier.ex
+++ b/lib/pleroma/web/activity_pub/transmogrifier.ex
@@ -16,12 +16,14 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
   alias Pleroma.Web.ActivityPub.ActivityPub
   alias Pleroma.Web.ActivityPub.Builder
   alias Pleroma.Web.ActivityPub.ObjectValidator
+  alias Pleroma.Web.ActivityPub.ObjectValidators.CommonFixes
   alias Pleroma.Web.ActivityPub.Pipeline
   alias Pleroma.Web.ActivityPub.Utils
   alias Pleroma.Web.ActivityPub.Visibility
   alias Pleroma.Web.Federator
 
   import Ecto.Query
+  import Pleroma.Web.Utils.Guards, only: [not_empty_string: 1]
 
   require Pleroma.Constants
 
@@ -41,6 +43,38 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
     |> fix_content_map()
     |> fix_addressing()
     |> fix_summary()
+    |> fix_history(&fix_object/1)
+  end
+
+  defp maybe_fix_object(%{"attributedTo" => _} = object), do: fix_object(object)
+  defp maybe_fix_object(object), do: object
+
+  defp fix_history(%{"formerRepresentations" => %{"orderedItems" => list}} = obj, fix_fun)
+       when is_list(list) do
+    update_in(obj["formerRepresentations"]["orderedItems"], fn h -> Enum.map(h, fix_fun) end)
+  end
+
+  defp fix_history(obj, _), do: obj
+
+  defp fix_recursive(obj, fun) do
+    # unlike Erlang, Elixir does not support recursive inline functions
+    # which would allow us to avoid reconstructing this on every recursion
+    rec_fun = fn
+      obj when is_map(obj) -> fix_recursive(obj, fun)
+      # there may be simple AP IDs in history (or object field)
+      obj -> obj
+    end
+
+    obj
+    |> fun.()
+    |> fix_history(rec_fun)
+    |> then(fn
+      %{"object" => object} = doc when is_map(object) ->
+        update_in(doc["object"], rec_fun)
+
+      apdoc ->
+        apdoc
+    end)
   end
 
   def fix_summary(%{"summary" => nil} = object) do
@@ -166,7 +200,7 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
 
   def fix_quote_url_and_maybe_fetch(object, options \\ []) do
     quote_url =
-      case Pleroma.Web.ActivityPub.ObjectValidators.CommonFixes.fix_quote_url(object) do
+      case CommonFixes.fix_quote_url(object) do
         %{"quoteUrl" => quote_url} -> quote_url
         _ -> nil
       end
@@ -336,6 +370,9 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
 
   def fix_tag(object), do: object
 
+  # prefer content over contentMap
+  def fix_content_map(%{"content" => content} = object) when not_empty_string(content), do: object
+
   # content map usually only has one language so this will do for now.
   def fix_content_map(%{"contentMap" => content_map} = object) do
     content_groups = Map.to_list(content_map)
@@ -370,11 +407,18 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
     end)
   end
 
-  def handle_incoming(data, options \\ [])
+  def handle_incoming(data, options \\ []) do
+    data
+    |> fix_recursive(&strip_internal_fields/1)
+    |> handle_incoming_normalized(options)
+  end
 
   # Flag objects are placed ahead of the ID check because Mastodon 2.8 and earlier send them
   # with nil ID.
-  def handle_incoming(%{"type" => "Flag", "object" => objects, "actor" => actor} = data, _options) do
+  defp handle_incoming_normalized(
+         %{"type" => "Flag", "object" => objects, "actor" => actor} = data,
+         _options
+       ) do
     with context <- data["context"] || Utils.generate_context_id(),
          content <- data["content"] || "",
          %User{} = actor <- User.get_cached_by_ap_id(actor),
@@ -395,16 +439,17 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
   end
 
   # disallow objects with bogus IDs
-  def handle_incoming(%{"id" => nil}, _options), do: :error
-  def handle_incoming(%{"id" => ""}, _options), do: :error
+  defp handle_incoming_normalized(%{"id" => nil}, _options), do: :error
+  defp handle_incoming_normalized(%{"id" => ""}, _options), do: :error
   # length of https:// = 8, should validate better, but good enough for now.
-  def handle_incoming(%{"id" => id}, _options) when is_binary(id) and byte_size(id) < 8,
-    do: :error
-
-  def handle_incoming(
-        %{"type" => "Listen", "object" => %{"type" => "Audio"} = object} = data,
-        options
-      ) do
+  defp handle_incoming_normalized(%{"id" => id}, _options)
+       when is_binary(id) and byte_size(id) < 8,
+       do: :error
+
+  defp handle_incoming_normalized(
+         %{"type" => "Listen", "object" => %{"type" => "Audio"} = object} = data,
+         options
+       ) do
     actor = Containment.get_actor(data)
 
     data =
@@ -446,25 +491,25 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
     "star" => "⭐"
   }
 
-  @doc "Rewrite misskey likes into EmojiReacts"
-  def handle_incoming(
-        %{
-          "type" => "Like",
-          "_misskey_reaction" => reaction
-        } = data,
-        options
-      ) do
+  # Rewrite misskey likes into EmojiReacts
+  defp handle_incoming_normalized(
+         %{
+           "type" => "Like",
+           "_misskey_reaction" => reaction
+         } = data,
+         options
+       ) do
     data
     |> Map.put("type", "EmojiReact")
     |> Map.put("content", @misskey_reactions[reaction] || reaction)
-    |> handle_incoming(options)
+    |> handle_incoming_normalized(options)
   end
 
-  def handle_incoming(
-        %{"type" => "Create", "object" => %{"type" => objtype, "id" => obj_id}} = data,
-        options
-      )
-      when objtype in ~w{Question Answer ChatMessage Audio Video Event Article Note Page Image} do
+  defp handle_incoming_normalized(
+         %{"type" => "Create", "object" => %{"type" => objtype, "id" => obj_id}} = data,
+         options
+       )
+       when objtype in ~w{Question Answer ChatMessage Audio Video Event Article Note Page Image} do
     fetch_options = Keyword.put(options, :depth, (options[:depth] || 0) + 1)
 
     object =
@@ -487,8 +532,8 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
     end
   end
 
-  def handle_incoming(%{"type" => type} = data, _options)
-      when type in ~w{Like EmojiReact Announce Add Remove} do
+  defp handle_incoming_normalized(%{"type" => type} = data, _options)
+       when type in ~w{Like EmojiReact Announce Add Remove} do
     with :ok <- ObjectValidator.fetch_actor_and_object(data),
          {:ok, activity, _meta} <-
            Pipeline.common_pipeline(data, local: false) do
@@ -498,11 +543,14 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
     end
   end
 
-  def handle_incoming(
-        %{"type" => type} = data,
-        _options
-      )
-      when type in ~w{Update Block Follow Accept Reject} do
+  defp handle_incoming_normalized(
+         %{"type" => type} = data,
+         _options
+       )
+       when type in ~w{Update Block Follow Accept Reject} do
+    fixed_obj = maybe_fix_object(data["object"])
+    data = if fixed_obj != nil, do: %{data | "object" => fixed_obj}, else: data
+
     with {:ok, %User{}} <- ObjectValidator.fetch_actor(data),
          {:ok, activity, _} <-
            Pipeline.common_pipeline(data, local: false) do
@@ -510,10 +558,10 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
     end
   end
 
-  def handle_incoming(
-        %{"type" => "Delete"} = data,
-        _options
-      ) do
+  defp handle_incoming_normalized(
+         %{"type" => "Delete"} = data,
+         _options
+       ) do
     with {:ok, activity, _} <-
            Pipeline.common_pipeline(data, local: false) do
       {:ok, activity}
@@ -536,15 +584,15 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
     end
   end
 
-  def handle_incoming(
-        %{
-          "type" => "Undo",
-          "object" => %{"type" => "Follow", "object" => followed},
-          "actor" => follower,
-          "id" => id
-        } = _data,
-        _options
-      ) do
+  defp handle_incoming_normalized(
+         %{
+           "type" => "Undo",
+           "object" => %{"type" => "Follow", "object" => followed},
+           "actor" => follower,
+           "id" => id
+         } = _data,
+         _options
+       ) do
     with %User{local: true} = followed <- User.get_cached_by_ap_id(followed),
          {:ok, %User{} = follower} <- User.get_or_fetch_by_ap_id(follower),
          {:ok, activity} <- ActivityPub.unfollow(follower, followed, id, false) do
@@ -555,46 +603,46 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
     end
   end
 
-  def handle_incoming(
-        %{
-          "type" => "Undo",
-          "object" => %{"type" => type}
-        } = data,
-        _options
-      )
-      when type in ["Like", "EmojiReact", "Announce", "Block"] do
+  defp handle_incoming_normalized(
+         %{
+           "type" => "Undo",
+           "object" => %{"type" => type}
+         } = data,
+         _options
+       )
+       when type in ["Like", "EmojiReact", "Announce", "Block"] do
     with {:ok, activity, _} <- Pipeline.common_pipeline(data, local: false) do
       {:ok, activity}
     end
   end
 
   # For Undos that don't have the complete object attached, try to find it in our database.
-  def handle_incoming(
-        %{
-          "type" => "Undo",
-          "object" => object
-        } = activity,
-        options
-      )
-      when is_binary(object) do
+  defp handle_incoming_normalized(
+         %{
+           "type" => "Undo",
+           "object" => object
+         } = activity,
+         options
+       )
+       when is_binary(object) do
     with %Activity{data: data} <- Activity.get_by_ap_id(object) do
       activity
       |> Map.put("object", data)
-      |> handle_incoming(options)
+      |> handle_incoming_normalized(options)
     else
       _e -> :error
     end
   end
 
-  def handle_incoming(
-        %{
-          "type" => "Move",
-          "actor" => origin_actor,
-          "object" => origin_actor,
-          "target" => target_actor
-        },
-        _options
-      ) do
+  defp handle_incoming_normalized(
+         %{
+           "type" => "Move",
+           "actor" => origin_actor,
+           "object" => origin_actor,
+           "target" => target_actor
+         },
+         _options
+       ) do
     with %User{} = origin_user <- User.get_cached_by_ap_id(origin_actor),
          {:ok, %User{} = target_user} <- User.get_or_fetch_by_ap_id(target_actor),
          true <- origin_actor in target_user.also_known_as do
@@ -604,7 +652,7 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
     end
   end
 
-  def handle_incoming(_, _), do: :error
+  defp handle_incoming_normalized(_, _), do: :error
 
   @spec get_obj_helper(String.t(), Keyword.t()) :: {:ok, Object.t()} | nil
   def get_obj_helper(id, options \\ []) do
@@ -716,6 +764,7 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
     |> set_reply_to_uri
     |> set_quote_url
     |> set_replies
+    |> CommonFixes.maybe_add_content_map()
     |> strip_internal_fields
     |> strip_internal_tags
     |> set_type
@@ -750,12 +799,11 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
       object_id
       |> Object.normalize(fetch: false)
       |> Map.get(:data)
-      |> prepare_object
 
     data =
       data
-      |> Map.put("object", object)
-      |> Map.merge(Utils.make_json_ld_header())
+      |> Map.put("object", prepare_object(object))
+      |> Map.merge(Utils.make_json_ld_header(object))
       |> Map.delete("bcc")
 
     {:ok, data}
@@ -763,14 +811,10 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
 
   def prepare_outgoing(%{"type" => "Update", "object" => %{"type" => objtype} = object} = data)
       when objtype in Pleroma.Constants.updatable_object_types() do
-    object =
-      object
-      |> prepare_object
-
     data =
       data
-      |> Map.put("object", object)
-      |> Map.merge(Utils.make_json_ld_header())
+      |> Map.put("object", prepare_object(object))
+      |> Map.merge(Utils.make_json_ld_header(object))
       |> Map.delete("bcc")
 
     {:ok, data}
@@ -840,7 +884,7 @@ defmodule Pleroma.Web.ActivityPub.Transmogrifier do
       data
       |> strip_internal_fields
       |> maybe_fix_object_url
-      |> Map.merge(Utils.make_json_ld_header())
+      |> Map.merge(Utils.make_json_ld_header(data))
 
     {:ok, data}
   end
diff --git a/lib/pleroma/web/activity_pub/utils.ex b/lib/pleroma/web/activity_pub/utils.ex
index 6c792804d..f30c92abf 100644
--- a/lib/pleroma/web/activity_pub/utils.ex
+++ b/lib/pleroma/web/activity_pub/utils.ex
@@ -20,6 +20,7 @@ defmodule Pleroma.Web.ActivityPub.Utils do
   alias Pleroma.Web.Router.Helpers
 
   import Ecto.Query
+  import Pleroma.Web.Utils.Guards, only: [not_empty_string: 1]
 
   require Logger
   require Pleroma.Constants
@@ -109,18 +110,24 @@ defmodule Pleroma.Web.ActivityPub.Utils do
     end
   end
 
-  def make_json_ld_header do
+  def make_json_ld_header(data \\ %{}) do
     %{
       "@context" => [
         "https://www.w3.org/ns/activitystreams",
         "#{Endpoint.url()}/schemas/litepub-0.1.jsonld",
         %{
-          "@language" => "und"
+          "@language" => get_language(data)
         }
       ]
     }
   end
 
+  defp get_language(%{"language" => language}) when not_empty_string(language) do
+    language
+  end
+
+  defp get_language(_), do: "und"
+
   def make_date do
     DateTime.utc_now() |> DateTime.to_iso8601()
   end
diff --git a/lib/pleroma/web/activity_pub/views/object_view.ex b/lib/pleroma/web/activity_pub/views/object_view.ex
index 63caa915c..13b5b2542 100644
--- a/lib/pleroma/web/activity_pub/views/object_view.ex
+++ b/lib/pleroma/web/activity_pub/views/object_view.ex
@@ -9,7 +9,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectView do
   alias Pleroma.Web.ActivityPub.Transmogrifier
 
   def render("object.json", %{object: %Object{} = object}) do
-    base = Pleroma.Web.ActivityPub.Utils.make_json_ld_header()
+    base = Pleroma.Web.ActivityPub.Utils.make_json_ld_header(object.data)
 
     additional = Transmogrifier.prepare_object(object.data)
     Map.merge(base, additional)
@@ -17,7 +17,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectView do
 
   def render("object.json", %{object: %Activity{data: %{"type" => activity_type}} = activity})
       when activity_type in ["Create", "Listen"] do
-    base = Pleroma.Web.ActivityPub.Utils.make_json_ld_header()
+    base = Pleroma.Web.ActivityPub.Utils.make_json_ld_header(activity.data)
     object = Object.normalize(activity, fetch: false)
 
     additional =
@@ -28,7 +28,7 @@ defmodule Pleroma.Web.ActivityPub.ObjectView do
   end
 
   def render("object.json", %{object: %Activity{} = activity}) do
-    base = Pleroma.Web.ActivityPub.Utils.make_json_ld_header()
+    base = Pleroma.Web.ActivityPub.Utils.make_json_ld_header(activity.data)
     object_id = Object.normalize(activity, id_only: true)
 
     additional =
diff --git a/lib/pleroma/web/activity_pub/views/user_view.ex b/lib/pleroma/web/activity_pub/views/user_view.ex
index cd485ed64..61975387b 100644
--- a/lib/pleroma/web/activity_pub/views/user_view.ex
+++ b/lib/pleroma/web/activity_pub/views/user_view.ex
@@ -127,7 +127,8 @@ defmodule Pleroma.Web.ActivityPub.UserView do
       "capabilities" => capabilities,
       "alsoKnownAs" => user.also_known_as,
       "vcard:bday" => birthday,
-      "webfinger" => "acct:#{User.full_nickname(user)}"
+      "webfinger" => "acct:#{User.full_nickname(user)}",
+      "published" => Pleroma.Web.CommonAPI.Utils.to_masto_date(user.inserted_at)
     }
     |> Map.merge(
       maybe_make_image(
diff --git a/lib/pleroma/web/api_spec.ex b/lib/pleroma/web/api_spec.ex
index 314782818..63409870e 100644
--- a/lib/pleroma/web/api_spec.ex
+++ b/lib/pleroma/web/api_spec.ex
@@ -139,7 +139,8 @@ defmodule Pleroma.Web.ApiSpec do
               "Search",
               "Status actions",
               "Media attachments",
-              "Bookmark folders"
+              "Bookmark folders",
+              "Tags"
             ]
           },
           %{
diff --git a/lib/pleroma/web/api_spec/operations/tag_operation.ex b/lib/pleroma/web/api_spec/operations/tag_operation.ex
new file mode 100644
index 000000000..ce4f4ad5b
--- /dev/null
+++ b/lib/pleroma/web/api_spec/operations/tag_operation.ex
@@ -0,0 +1,103 @@
+defmodule Pleroma.Web.ApiSpec.TagOperation do
+  alias OpenApiSpex.Operation
+  alias OpenApiSpex.Schema
+  alias Pleroma.Web.ApiSpec.Schemas.ApiError
+  alias Pleroma.Web.ApiSpec.Schemas.Tag
+
+  def open_api_operation(action) do
+    operation = String.to_existing_atom("#{action}_operation")
+    apply(__MODULE__, operation, [])
+  end
+
+  def show_operation do
+    %Operation{
+      tags: ["Tags"],
+      summary: "Hashtag",
+      description: "View a hashtag",
+      security: [%{"oAuth" => ["read"]}],
+      parameters: [id_param()],
+      operationId: "TagController.show",
+      responses: %{
+        200 => Operation.response("Hashtag", "application/json", Tag),
+        404 => Operation.response("Not Found", "application/json", ApiError)
+      }
+    }
+  end
+
+  def follow_operation do
+    %Operation{
+      tags: ["Tags"],
+      summary: "Follow a hashtag",
+      description: "Follow a hashtag",
+      security: [%{"oAuth" => ["write:follows"]}],
+      parameters: [id_param()],
+      operationId: "TagController.follow",
+      responses: %{
+        200 => Operation.response("Hashtag", "application/json", Tag),
+        404 => Operation.response("Not Found", "application/json", ApiError)
+      }
+    }
+  end
+
+  def unfollow_operation do
+    %Operation{
+      tags: ["Tags"],
+      summary: "Unfollow a hashtag",
+      description: "Unfollow a hashtag",
+      security: [%{"oAuth" => ["write:follows"]}],
+      parameters: [id_param()],
+      operationId: "TagController.unfollow",
+      responses: %{
+        200 => Operation.response("Hashtag", "application/json", Tag),
+        404 => Operation.response("Not Found", "application/json", ApiError)
+      }
+    }
+  end
+
+  def show_followed_operation do
+    %Operation{
+      tags: ["Tags"],
+      summary: "Followed hashtags",
+      description: "View a list of hashtags the currently authenticated user is following",
+      parameters: pagination_params(),
+      security: [%{"oAuth" => ["read:follows"]}],
+      operationId: "TagController.show_followed",
+      responses: %{
+        200 =>
+          Operation.response("Hashtags", "application/json", %Schema{
+            type: :array,
+            items: Tag
+          }),
+        403 => Operation.response("Forbidden", "application/json", ApiError),
+        404 => Operation.response("Not Found", "application/json", ApiError)
+      }
+    }
+  end
+
+  defp id_param do
+    Operation.parameter(
+      :id,
+      :path,
+      %Schema{type: :string},
+      "Name of the hashtag"
+    )
+  end
+
+  def pagination_params do
+    [
+      Operation.parameter(:max_id, :query, :integer, "Return items older than this ID"),
+      Operation.parameter(
+        :min_id,
+        :query,
+        :integer,
+        "Return the oldest items newer than this ID"
+      ),
+      Operation.parameter(
+        :limit,
+        :query,
+        %Schema{type: :integer, default: 20},
+        "Maximum number of items to return. Will be ignored if it's more than 40"
+      )
+    ]
+  end
+end
diff --git a/lib/pleroma/web/api_spec/schemas/tag.ex b/lib/pleroma/web/api_spec/schemas/tag.ex
index 66bf0ca71..05ff10cd3 100644
--- a/lib/pleroma/web/api_spec/schemas/tag.ex
+++ b/lib/pleroma/web/api_spec/schemas/tag.ex
@@ -17,11 +17,22 @@ defmodule Pleroma.Web.ApiSpec.Schemas.Tag do
         type: :string,
         format: :uri,
         description: "A link to the hashtag on the instance"
+      },
+      following: %Schema{
+        type: :boolean,
+        description: "Whether the authenticated user is following the hashtag"
+      },
+      history: %Schema{
+        type: :array,
+        items: %Schema{type: :string},
+        description:
+          "A list of historical uses of the hashtag (not implemented, for compatibility only)"
       }
     },
     example: %{
       name: "cofe",
-      url: "https://lain.com/tag/cofe"
+      url: "https://lain.com/tag/cofe",
+      following: false
     }
   })
 end
diff --git a/lib/pleroma/web/common_api/activity_draft.ex b/lib/pleroma/web/common_api/activity_draft.ex
index 8aa1e258d..4220757df 100644
--- a/lib/pleroma/web/common_api/activity_draft.ex
+++ b/lib/pleroma/web/common_api/activity_draft.ex
@@ -11,6 +11,9 @@ defmodule Pleroma.Web.CommonAPI.ActivityDraft do
   alias Pleroma.Web.CommonAPI
   alias Pleroma.Web.CommonAPI.Utils
 
+  import Pleroma.EctoType.ActivityPub.ObjectValidators.LanguageCode,
+    only: [good_locale_code?: 1]
+
   import Pleroma.Web.Gettext
   import Pleroma.Web.Utils.Guards, only: [not_empty_string: 1]
 
@@ -38,6 +41,7 @@ defmodule Pleroma.Web.CommonAPI.ActivityDraft do
             cc: [],
             context: nil,
             sensitive: false,
+            language: nil,
             object: nil,
             preview?: false,
             changes: %{}
@@ -64,6 +68,7 @@ defmodule Pleroma.Web.CommonAPI.ActivityDraft do
     |> content()
     |> with_valid(&to_and_cc/1)
     |> with_valid(&context/1)
+    |> with_valid(&language/1)
     |> sensitive()
     |> with_valid(&object/1)
     |> preview?()
@@ -249,6 +254,16 @@ defmodule Pleroma.Web.CommonAPI.ActivityDraft do
     %__MODULE__{draft | sensitive: sensitive}
   end
 
+  defp language(draft) do
+    language = draft.params[:language]
+
+    if good_locale_code?(language) do
+      %__MODULE__{draft | language: language}
+    else
+      draft
+    end
+  end
+
   defp object(draft) do
     emoji = Map.merge(Pleroma.Emoji.Formatter.get_emoji_map(draft.full_payload), draft.emoji)
 
@@ -288,6 +303,7 @@ defmodule Pleroma.Web.CommonAPI.ActivityDraft do
         "mediaType" => Utils.get_content_type(draft.params[:content_type])
       })
       |> Map.put("generator", draft.params[:generator])
+      |> Map.put("language", draft.language)
 
     %__MODULE__{draft | object: object}
   end
diff --git a/lib/pleroma/web/mastodon_api/controllers/tag_controller.ex b/lib/pleroma/web/mastodon_api/controllers/tag_controller.ex
new file mode 100644
index 000000000..21c21e984
--- /dev/null
+++ b/lib/pleroma/web/mastodon_api/controllers/tag_controller.ex
@@ -0,0 +1,77 @@
+defmodule Pleroma.Web.MastodonAPI.TagController do
+  @moduledoc "Hashtag routes for mastodon API"
+  use Pleroma.Web, :controller
+
+  alias Pleroma.Hashtag
+  alias Pleroma.Pagination
+  alias Pleroma.User
+
+  import Pleroma.Web.ControllerHelper,
+    only: [
+      add_link_headers: 2
+    ]
+
+  plug(Pleroma.Web.ApiSpec.CastAndValidate)
+
+  plug(
+    Pleroma.Web.Plugs.OAuthScopesPlug,
+    %{scopes: ["read"]} when action in [:show]
+  )
+
+  plug(
+    Pleroma.Web.Plugs.OAuthScopesPlug,
+    %{scopes: ["read:follows"]} when action in [:show_followed]
+  )
+
+  plug(
+    Pleroma.Web.Plugs.OAuthScopesPlug,
+    %{scopes: ["write:follows"]} when action in [:follow, :unfollow]
+  )
+
+  defdelegate open_api_operation(action), to: Pleroma.Web.ApiSpec.TagOperation
+
+  def show(conn, %{id: id}) do
+    with %Hashtag{} = hashtag <- Hashtag.get_by_name(id) do
+      render(conn, "show.json", tag: hashtag, for_user: conn.assigns.user)
+    else
+      _ -> conn |> render_error(:not_found, "Hashtag not found")
+    end
+  end
+
+  def follow(conn, %{id: id}) do
+    with %Hashtag{} = hashtag <- Hashtag.get_by_name(id),
+         %User{} = user <- conn.assigns.user,
+         {:ok, _} <-
+           User.follow_hashtag(user, hashtag) do
+      render(conn, "show.json", tag: hashtag, for_user: user)
+    else
+      _ -> render_error(conn, :not_found, "Hashtag not found")
+    end
+  end
+
+  def unfollow(conn, %{id: id}) do
+    with %Hashtag{} = hashtag <- Hashtag.get_by_name(id),
+         %User{} = user <- conn.assigns.user,
+         {:ok, _} <-
+           User.unfollow_hashtag(user, hashtag) do
+      render(conn, "show.json", tag: hashtag, for_user: user)
+    else
+      _ -> render_error(conn, :not_found, "Hashtag not found")
+    end
+  end
+
+  def show_followed(conn, params) do
+    with %{assigns: %{user: %User{} = user}} <- conn do
+      params = Map.put(params, :id_type, :integer)
+
+      hashtags =
+        user
+        |> User.HashtagFollow.followed_hashtags_query()
+        |> Pagination.fetch_paginated(params)
+
+      conn
+      |> add_link_headers(hashtags)
+      |> render("index.json", tags: hashtags, for_user: user)
+    end
+  end
+end
diff --git a/lib/pleroma/web/mastodon_api/controllers/timeline_controller.ex b/lib/pleroma/web/mastodon_api/controllers/timeline_controller.ex
index 293c61b41..5ee74a80e 100644
--- a/lib/pleroma/web/mastodon_api/controllers/timeline_controller.ex
+++ b/lib/pleroma/web/mastodon_api/controllers/timeline_controller.ex
@@ -40,6 +40,11 @@ defmodule Pleroma.Web.MastodonAPI.TimelineController do
 
   # GET /api/v1/timelines/home
   def home(%{assigns: %{user: user}} = conn, params) do
+    followed_hashtags =
+      user
+      |> User.followed_hashtags()
+      |> Enum.map(& &1.id)
+
     params =
       params
       |> Map.put(:type, ["Create", "Announce"])
@@ -49,6 +54,7 @@ defmodule Pleroma.Web.MastodonAPI.TimelineController do
       |> Map.put(:announce_filtering_user, user)
       |> Map.put(:user, user)
       |> Map.put(:local_only, params[:local])
+      |> Map.put(:followed_hashtags, followed_hashtags)
       |> Map.delete(:local)
 
     activities =
diff --git a/lib/pleroma/web/mastodon_api/views/status_view.ex b/lib/pleroma/web/mastodon_api/views/status_view.ex
index 3bf870c24..10966edd6 100644
--- a/lib/pleroma/web/mastodon_api/views/status_view.ex
+++ b/lib/pleroma/web/mastodon_api/views/status_view.ex
@@ -227,7 +227,7 @@ defmodule Pleroma.Web.MastodonAPI.StatusView do
       mentions: mentions,
       tags: reblogged[:tags] || [],
       application: build_application(object.data["generator"]),
-      language: nil,
+      language: get_language(object),
       emojis: [],
       pleroma: %{
         local: activity.local,
@@ -445,7 +445,7 @@ defmodule Pleroma.Web.MastodonAPI.StatusView do
       mentions: mentions,
       tags: build_tags(tags),
       application: build_application(object.data["generator"]),
-      language: nil,
+      language: get_language(object),
       emojis: build_emojis(object.data["emoji"]),
       pleroma: %{
         local: activity.local,
@@ -829,6 +829,10 @@ defmodule Pleroma.Web.MastodonAPI.StatusView do
     Utils.get_content_type(nil)
   end
 
+  defp get_language(%{data: %{"language" => "und"}}), do: nil
+
+  defp get_language(object), do: object.data["language"]
+
   defp proxied_url(url, page_url_data) do
     if is_binary(url) do
       build_image_url(URI.parse(url), page_url_data) |> MediaProxy.url()
diff --git a/lib/pleroma/web/mastodon_api/views/tag_view.ex b/lib/pleroma/web/mastodon_api/views/tag_view.ex
new file mode 100644
index 000000000..e24d423c2
--- /dev/null
+++ b/lib/pleroma/web/mastodon_api/views/tag_view.ex
@@ -0,0 +1,25 @@
+defmodule Pleroma.Web.MastodonAPI.TagView do
+  use Pleroma.Web, :view
+  alias Pleroma.User
+  alias Pleroma.Web.Router.Helpers
+
+  def render("index.json", %{tags: tags, for_user: user}) do
+    safe_render_many(tags, __MODULE__, "show.json", %{for_user: user})
+  end
+
+  def render("show.json", %{tag: tag, for_user: user}) do
+    following =
+      with %User{} <- user do
+        User.following_hashtag?(user, tag)
+      else
+        _ -> false
+      end
+
+    %{
+      name: tag.name,
+      url: Helpers.tag_feed_url(Pleroma.Web.Endpoint, :feed, tag.name),
+      history: [],
+      following: following
+    }
+  end
+end
diff --git a/lib/pleroma/web/media_proxy/media_proxy_controller.ex b/lib/pleroma/web/media_proxy/media_proxy_controller.ex
index 0b446e0a6..a0aafc32e 100644
--- a/lib/pleroma/web/media_proxy/media_proxy_controller.ex
+++ b/lib/pleroma/web/media_proxy/media_proxy_controller.ex
@@ -71,11 +71,15 @@ defmodule Pleroma.Web.MediaProxy.MediaProxyController do
           drop_static_param_and_redirect(conn)
 
         content_type == "image/gif" ->
-          redirect(conn, external: media_proxy_url)
+          conn
+          |> put_status(301)
+          |> redirect(external: media_proxy_url)
 
         min_content_length_for_preview() > 0 and content_length > 0 and
             content_length < min_content_length_for_preview() ->
-          redirect(conn, external: media_proxy_url)
+          conn
+          |> put_status(301)
+          |> redirect(external: media_proxy_url)
 
         true ->
           handle_preview(content_type, conn, media_proxy_url)
diff --git a/lib/pleroma/web/metadata/providers/open_graph.ex b/lib/pleroma/web/metadata/providers/open_graph.ex
index fa5fbe553..604434df2 100644
--- a/lib/pleroma/web/metadata/providers/open_graph.ex
+++ b/lib/pleroma/web/metadata/providers/open_graph.ex
@@ -78,10 +78,10 @@ defmodule Pleroma.Web.Metadata.Providers.OpenGraph do
           # object when a Video or GIF is attached it will display that in Whatsapp Rich Preview.
           case Utils.fetch_media_type(@media_types, url["mediaType"]) do
             "audio" ->
-              [
-                {:meta, [property: "og:audio", content: MediaProxy.url(url["href"])], []}
-                | acc
-              ]
+              acc ++
+                [
+                  {:meta, [property: "og:audio", content: MediaProxy.url(url["href"])], []}
+                ]
 
             # Not using preview_url for this. It saves bandwidth, but the image dimensions will
             # be wrong. We generate it on the fly and have no way to capture or analyze the
@@ -89,18 +89,18 @@ defmodule Pleroma.Web.Metadata.Providers.OpenGraph do
             # in timelines too, but you can get clever with the aspect ratio metadata as a
             # workaround.
             "image" ->
-              [
-                {:meta, [property: "og:image", content: MediaProxy.url(url["href"])], []},
-                {:meta, [property: "og:image:alt", content: attachment["name"]], []}
-                | acc
-              ]
+              (acc ++
+                 [
+                   {:meta, [property: "og:image", content: MediaProxy.url(url["href"])], []},
+                   {:meta, [property: "og:image:alt", content: attachment["name"]], []}
+                 ])
               |> maybe_add_dimensions(url)
 
             "video" ->
-              [
-                {:meta, [property: "og:video", content: MediaProxy.url(url["href"])], []}
-                | acc
-              ]
+              (acc ++
+                 [
+                   {:meta, [property: "og:video", content: MediaProxy.url(url["href"])], []}
+                 ])
               |> maybe_add_dimensions(url)
               |> maybe_add_video_thumbnail(url)
 
diff --git a/lib/pleroma/web/metadata/providers/twitter_card.ex b/lib/pleroma/web/metadata/providers/twitter_card.ex
index 7f50877c3..212fa85ed 100644
--- a/lib/pleroma/web/metadata/providers/twitter_card.ex
+++ b/lib/pleroma/web/metadata/providers/twitter_card.ex
@@ -61,13 +61,13 @@ defmodule Pleroma.Web.Metadata.Providers.TwitterCard do
         Enum.reduce(attachment["url"], [], fn url, acc ->
           case Utils.fetch_media_type(@media_types, url["mediaType"]) do
             "audio" ->
-              [
-                {:meta, [name: "twitter:card", content: "player"], []},
-                {:meta, [name: "twitter:player:width", content: "480"], []},
-                {:meta, [name: "twitter:player:height", content: "80"], []},
-                {:meta, [name: "twitter:player", content: player_url(id)], []}
-                | acc
-              ]
+              acc ++
+                [
+                  {:meta, [name: "twitter:card", content: "player"], []},
+                  {:meta, [name: "twitter:player:width", content: "480"], []},
+                  {:meta, [name: "twitter:player:height", content: "80"], []},
+                  {:meta, [name: "twitter:player", content: player_url(id)], []}
+                ]
 
             # Not using preview_url for this. It saves bandwidth, but the image dimensions will
             # be wrong. We generate it on the fly and have no way to capture or analyze the
@@ -75,16 +75,16 @@ defmodule Pleroma.Web.Metadata.Providers.TwitterCard do
             # in timelines too, but you can get clever with the aspect ratio metadata as a
             # workaround.
             "image" ->
-              [
-                {:meta, [name: "twitter:card", content: "summary_large_image"], []},
-                {:meta,
+              (acc ++
                  [
-                   name: "twitter:image",
-                   content: MediaProxy.url(url["href"])
-                 ], []},
-                {:meta, [name: "twitter:image:alt", content: truncate(attachment["name"])], []}
-                | acc
-              ]
+                   {:meta, [name: "twitter:card", content: "summary_large_image"], []},
+                   {:meta,
+                    [
+                      name: "twitter:image",
+                      content: MediaProxy.url(url["href"])
+                    ], []},
+                   {:meta, [name: "twitter:image:alt", content: truncate(attachment["name"])], []}
+                 ])
               |> maybe_add_dimensions(url)
 
             "video" ->
@@ -92,17 +92,17 @@ defmodule Pleroma.Web.Metadata.Providers.TwitterCard do
               height = url["height"] || 480
               width = url["width"] || 480
 
-              [
-                {:meta, [name: "twitter:card", content: "player"], []},
-                {:meta, [name: "twitter:player", content: player_url(id)], []},
-                {:meta, [name: "twitter:player:width", content: "#{width}"], []},
-                {:meta, [name: "twitter:player:height", content: "#{height}"], []},
-                {:meta, [name: "twitter:player:stream", content: MediaProxy.url(url["href"])],
-                 []},
-                {:meta, [name: "twitter:player:stream:content_type", content: url["mediaType"]],
-                 []}
-                | acc
-              ]
+              acc ++
+                [
+                  {:meta, [name: "twitter:card", content: "player"], []},
+                  {:meta, [name: "twitter:player", content: player_url(id)], []},
+                  {:meta, [name: "twitter:player:width", content: "#{width}"], []},
+                  {:meta, [name: "twitter:player:height", content: "#{height}"], []},
+                  {:meta, [name: "twitter:player:stream", content: MediaProxy.url(url["href"])],
+                   []},
+                  {:meta, [name: "twitter:player:stream:content_type", content: url["mediaType"]],
+                   []}
+                ]
 
             _ ->
               acc
diff --git a/lib/pleroma/web/plugs/ap_client_api_enabled_plug.ex b/lib/pleroma/web/plugs/ap_client_api_enabled_plug.ex
new file mode 100644
index 000000000..6807673f9
--- /dev/null
+++ b/lib/pleroma/web/plugs/ap_client_api_enabled_plug.ex
@@ -0,0 +1,34 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2024 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.Plugs.APClientApiEnabledPlug do
+  import Plug.Conn
+  import Phoenix.Controller, only: [text: 2]
+
+  @config_impl Application.compile_env(:pleroma, [__MODULE__, :config_impl], Pleroma.Config)
+  @enabled_path [:activitypub, :client_api_enabled]
+
+  def init(options \\ []), do: Map.new(options)
+
+  def call(conn, %{allow_server: true}) do
+    if @config_impl.get(@enabled_path, false) do
+      conn
+    else
+      conn
+      |> assign(:user, nil)
+      |> assign(:token, nil)
+    end
+  end
+
+  def call(conn, _) do
+    if @config_impl.get(@enabled_path, false) do
+      conn
+    else
+      conn
+      |> put_status(:forbidden)
+      |> text("C2S not enabled")
+      |> halt()
+    end
+  end
+end
diff --git a/lib/pleroma/web/plugs/http_signature_plug.ex b/lib/pleroma/web/plugs/http_signature_plug.ex
index 67974599a..2e16212ce 100644
--- a/lib/pleroma/web/plugs/http_signature_plug.ex
+++ b/lib/pleroma/web/plugs/http_signature_plug.ex
@@ -19,8 +19,16 @@ defmodule Pleroma.Web.Plugs.HTTPSignaturePlug do
     options
   end
 
-  def call(%{assigns: %{valid_signature: true}} = conn, _opts) do
-    conn
+  def call(%{assigns: %{valid_signature: true}} = conn, _opts), do: conn
+
+  # skip for C2S requests from authenticated users
+  def call(%{assigns: %{user: %Pleroma.User{}}} = conn, _opts) do
+    if get_format(conn) in ["json", "activity+json"] do
+      # ensure access token is provided for 2FA
+      Pleroma.Web.Plugs.EnsureAuthenticatedPlug.call(conn, %{})
+    else
+      conn
+    end
   end
 
   def call(conn, _opts) do
diff --git a/lib/pleroma/web/rich_media/card.ex b/lib/pleroma/web/rich_media/card.ex
index abad4957e..6b4bb9555 100644
--- a/lib/pleroma/web/rich_media/card.ex
+++ b/lib/pleroma/web/rich_media/card.ex
@@ -54,7 +54,10 @@ defmodule Pleroma.Web.RichMedia.Card do
 
   @spec get_by_url(String.t() | nil) :: t() | nil | :error
   def get_by_url(url) when is_binary(url) do
-    if @config_impl.get([:rich_media, :enabled]) do
+    host = URI.parse(url).host
+
+    with true <- @config_impl.get([:rich_media, :enabled]),
+         true <- host not in @config_impl.get([:rich_media, :ignore_hosts], []) do
       url_hash = url_to_hash(url)
 
       @cachex.fetch!(:rich_media_cache, url_hash, fn _ ->
@@ -69,7 +72,7 @@ defmodule Pleroma.Web.RichMedia.Card do
         end
       end)
     else
-      :error
+      false -> :error
     end
   end
 
@@ -77,7 +80,10 @@ defmodule Pleroma.Web.RichMedia.Card do
 
   @spec get_or_backfill_by_url(String.t(), keyword()) :: t() | nil
   def get_or_backfill_by_url(url, opts \\ []) do
-    if @config_impl.get([:rich_media, :enabled]) do
+    host = URI.parse(url).host
+
+    with true <- @config_impl.get([:rich_media, :enabled]),
+         true <- host not in @config_impl.get([:rich_media, :ignore_hosts], []) do
       case get_by_url(url) do
         %__MODULE__{} = card ->
           card
@@ -94,7 +100,7 @@ defmodule Pleroma.Web.RichMedia.Card do
           nil
       end
     else
-      nil
+      false -> nil
     end
   end
 
diff --git a/lib/pleroma/web/rich_media/parsers/meta_tags_parser.ex b/lib/pleroma/web/rich_media/parsers/meta_tags_parser.ex
index 320a5f515..c42e2c96b 100644
--- a/lib/pleroma/web/rich_media/parsers/meta_tags_parser.ex
+++ b/lib/pleroma/web/rich_media/parsers/meta_tags_parser.ex
@@ -9,7 +9,7 @@ defmodule Pleroma.Web.RichMedia.Parsers.MetaTagsParser do
     |> Enum.reduce(data, fn el, acc ->
       attributes = normalize_attributes(el, prefix, key_name, value_name)
 
-      Map.merge(acc, attributes)
+      Map.merge(attributes, acc)
     end)
     |> maybe_put_title(html)
   end
diff --git a/lib/pleroma/web/rich_media/parsers/twitter_card.ex b/lib/pleroma/web/rich_media/parsers/twitter_card.ex
index cc653729d..6f6f8b2ae 100644
--- a/lib/pleroma/web/rich_media/parsers/twitter_card.ex
+++ b/lib/pleroma/web/rich_media/parsers/twitter_card.ex
@@ -11,5 +11,16 @@ defmodule Pleroma.Web.RichMedia.Parsers.TwitterCard do
     |> MetaTagsParser.parse(html, "og", "property")
     |> MetaTagsParser.parse(html, "twitter", "name")
     |> MetaTagsParser.parse(html, "twitter", "property")
+    |> filter_tags()
+  end
+
+  defp filter_tags(tags) do
+    Map.filter(tags, fn {k, _v} ->
+      cond do
+        k in ["card", "description", "image", "title", "ttl", "type", "url"] -> true
+        String.starts_with?(k, "image:") -> true
+        true -> false
+      end
+    end)
   end
 end
diff --git a/lib/pleroma/web/router.ex b/lib/pleroma/web/router.ex
index 0423ca9e2..bf8ebf3e4 100644
--- a/lib/pleroma/web/router.ex
+++ b/lib/pleroma/web/router.ex
@@ -755,6 +755,11 @@ defmodule Pleroma.Web.Router do
 
     get("/announcements", AnnouncementController, :index)
     post("/announcements/:id/dismiss", AnnouncementController, :mark_read)
+
+    get("/tags/:id", TagController, :show)
+    post("/tags/:id/follow", TagController, :follow)
+    post("/tags/:id/unfollow", TagController, :unfollow)
+    get("/followed_tags", TagController, :show_followed)
   end
 
   scope "/api/v1", Pleroma.Web.MastodonAPI do
@@ -902,9 +907,20 @@ defmodule Pleroma.Web.Router do
   # Client to Server (C2S) AP interactions
   pipeline :activitypub_client do
     plug(:ap_service_actor)
+    plug(Pleroma.Web.Plugs.APClientApiEnabledPlug)
+    plug(:fetch_session)
+    plug(:authenticate)
+    plug(:after_auth)
+  end
+
+  # AP interactions used by both S2S and C2S
+  pipeline :activitypub_server_or_client do
+    plug(:ap_service_actor)
     plug(:fetch_session)
     plug(:authenticate)
+    plug(Pleroma.Web.Plugs.APClientApiEnabledPlug, allow_server: true)
     plug(:after_auth)
+    plug(:http_signature)
   end
 
   scope "/", Pleroma.Web.ActivityPub do
@@ -913,11 +929,15 @@ defmodule Pleroma.Web.Router do
     get("/api/ap/whoami", ActivityPubController, :whoami)
     get("/users/:nickname/inbox", ActivityPubController, :read_inbox)
 
-    get("/users/:nickname/outbox", ActivityPubController, :outbox)
     post("/users/:nickname/outbox", ActivityPubController, :update_outbox)
     post("/api/ap/upload_media", ActivityPubController, :upload_media)
+  end
+
+  scope "/", Pleroma.Web.ActivityPub do
+    pipe_through([:activitypub_server_or_client])
+
+    get("/users/:nickname/outbox", ActivityPubController, :outbox)
 
-    # The following two are S2S as well, see `ActivityPub.fetch_follow_information_for_user/1`:
     get("/users/:nickname/followers", ActivityPubController, :followers)
     get("/users/:nickname/following", ActivityPubController, :following)
     get("/users/:nickname/collections/featured", ActivityPubController, :pinned)
diff --git a/lib/pleroma/web/streamer.ex b/lib/pleroma/web/streamer.ex
index 76dc0f42d..cc149e04c 100644
--- a/lib/pleroma/web/streamer.ex
+++ b/lib/pleroma/web/streamer.ex
@@ -19,6 +19,7 @@ defmodule Pleroma.Web.Streamer do
   alias Pleroma.Web.OAuth.Token
   alias Pleroma.Web.Plugs.OAuthScopesPlug
   alias Pleroma.Web.StreamerView
+  require Pleroma.Constants
 
   @registry Pleroma.Web.StreamerRegistry
 
@@ -305,7 +306,17 @@ defmodule Pleroma.Web.Streamer do
       User.get_recipients_from_activity(item)
       |> Enum.map(fn %{id: id} -> "user:#{id}" end)
 
-    Enum.each(recipient_topics, fn topic ->
+    hashtag_recipients =
+      if Pleroma.Constants.as_public() in item.recipients do
+        Pleroma.Hashtag.get_recipients_for_activity(item)
+        |> Enum.map(fn id -> "user:#{id}" end)
+      else
+        []
+      end
+
+    all_recipients = Enum.uniq(recipient_topics ++ hashtag_recipients)
+
+    Enum.each(all_recipients, fn topic ->
       push_to_socket(topic, item)
     end)
   end