diff --git a/CHANGELOG.md b/CHANGELOG.md
index 899a6c823..14d9dbfa3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,24 @@ Changelog
 
 All notable changes to this project will be documented in this file.
 
+## [4.1.12] - 2024-01-24
+
+### Fixed
+
+- Fix error when processing remote files with unusually long names ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28823))
+- Fix processing of compacted single-item JSON-LD collections ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28816))
+- Retry 401 errors on replies fetching ([ShadowJonathan](https://github.com/mastodon/mastodon/pull/28788))
+- Fix `RecordNotUnique` errors in LinkCrawlWorker ([tribela](https://github.com/mastodon/mastodon/pull/28748))
+- Fix Mastodon not correctly processing HTTP Signatures with query strings ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28443), [ClearlyClaire](https://github.com/mastodon/mastodon/pull/28476))
+- Fix potential redirection loop of streaming endpoint ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28665))
+- Fix streaming API redirection ignoring the port of `streaming_api_base_url` ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28558))
+- Fix `Undo Announce` activity not being sent to non-follower authors ([MitarashiDango](https://github.com/mastodon/mastodon/pull/18482))
+- Fix `LinkCrawlWorker` error when encountering empty OEmbed response ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28268))
+
+### Security
+
+- Add rate-limit of TOTP authentication attempts at controller level ([ClearlyClaire](https://github.com/mastodon/mastodon/pull/28801))
+
 ## [4.1.11] - 2023-12-04
 
 ### Changed
diff --git a/app/controllers/api/v1/streaming_controller.rb b/app/controllers/api/v1/streaming_controller.rb
index b23a60170..843065adb 100644
--- a/app/controllers/api/v1/streaming_controller.rb
+++ b/app/controllers/api/v1/streaming_controller.rb
@@ -2,7 +2,7 @@
 
 class Api::V1::StreamingController < Api::BaseController
   def index
-    if Rails.configuration.x.streaming_api_base_url == request.host
+    if same_host?
       not_found
     else
       redirect_to streaming_api_url, status: 301
@@ -11,9 +11,16 @@ class Api::V1::StreamingController < Api::BaseController
 
   private
 
+  def same_host?
+    base_url = Addressable::URI.parse(Rails.configuration.x.streaming_api_base_url)
+    request.host == base_url.host && request.port == (base_url.port || 80)
+  end
+
   def streaming_api_url
     Addressable::URI.parse(request.url).tap do |uri|
-      uri.host = Addressable::URI.parse(Rails.configuration.x.streaming_api_base_url).host
+      base_url = Addressable::URI.parse(Rails.configuration.x.streaming_api_base_url)
+      uri.host = base_url.host
+      uri.port = base_url.port
     end.to_s
   end
 end
diff --git a/app/controllers/auth/sessions_controller.rb b/app/controllers/auth/sessions_controller.rb
index afcf8b24b..17d75e1bb 100644
--- a/app/controllers/auth/sessions_controller.rb
+++ b/app/controllers/auth/sessions_controller.rb
@@ -1,6 +1,10 @@
 # frozen_string_literal: true
 
 class Auth::SessionsController < Devise::SessionsController
+  include Redisable
+
+  MAX_2FA_ATTEMPTS_PER_HOUR = 10
+
   layout 'auth'
 
   skip_before_action :require_no_authentication, only: [:create]
@@ -136,9 +140,23 @@ class Auth::SessionsController < Devise::SessionsController
     session.delete(:attempt_user_updated_at)
   end
 
+  def clear_2fa_attempt_from_user(user)
+    redis.del(second_factor_attempts_key(user))
+  end
+
+  def check_second_factor_rate_limits(user)
+    attempts, = redis.multi do |multi|
+      multi.incr(second_factor_attempts_key(user))
+      multi.expire(second_factor_attempts_key(user), 1.hour)
+    end
+
+    attempts >= MAX_2FA_ATTEMPTS_PER_HOUR
+  end
+
   def on_authentication_success(user, security_measure)
     @on_authentication_success_called = true
 
+    clear_2fa_attempt_from_user(user)
     clear_attempt_from_session
 
     user.update_sign_in!(new_sign_in: true)
@@ -170,4 +188,8 @@ class Auth::SessionsController < Devise::SessionsController
       user_agent: request.user_agent
     )
   end
+
+  def second_factor_attempts_key(user)
+    "2fa_auth_attempts:#{user.id}:#{Time.now.utc.hour}"
+  end
 end
diff --git a/app/controllers/concerns/signature_verification.rb b/app/controllers/concerns/signature_verification.rb
index 9c04ab4ca..3ac557e7f 100644
--- a/app/controllers/concerns/signature_verification.rb
+++ b/app/controllers/concerns/signature_verification.rb
@@ -91,14 +91,23 @@ module SignatureVerification
     raise SignatureVerificationError, "Public key not found for key #{signature_params['keyId']}" if actor.nil?
 
     signature             = Base64.decode64(signature_params['signature'])
-    compare_signed_string = build_signed_string
+    compare_signed_string = build_signed_string(include_query_string: true)
 
     return actor unless verify_signature(actor, signature, compare_signed_string).nil?
 
+    # Compatibility quirk with older Mastodon versions
+    compare_signed_string = build_signed_string(include_query_string: false)
+    return actor unless verify_signature(actor, signature, compare_signed_string).nil?
+
     actor = stoplight_wrap_request { actor_refresh_key!(actor) }
 
     raise SignatureVerificationError, "Could not refresh public key #{signature_params['keyId']}" if actor.nil?
 
+    compare_signed_string = build_signed_string(include_query_string: true)
+    return actor unless verify_signature(actor, signature, compare_signed_string).nil?
+
+    # Compatibility quirk with older Mastodon versions
+    compare_signed_string = build_signed_string(include_query_string: false)
     return actor unless verify_signature(actor, signature, compare_signed_string).nil?
 
     fail_with! "Verification failed for #{actor.to_log_human_identifier} #{actor.uri} using rsa-sha256 (RSASSA-PKCS1-v1_5 with SHA-256)", signed_string: compare_signed_string, signature: signature_params['signature']
@@ -177,16 +186,24 @@ module SignatureVerification
     nil
   end
 
-  def build_signed_string
+  def build_signed_string(include_query_string: true)
     signed_headers.map do |signed_header|
-      if signed_header == Request::REQUEST_TARGET
-        "#{Request::REQUEST_TARGET}: #{request.method.downcase} #{request.path}"
-      elsif signed_header == '(created)'
+      case signed_header
+      when Request::REQUEST_TARGET
+        if include_query_string
+          "#{Request::REQUEST_TARGET}: #{request.method.downcase} #{request.original_fullpath}"
+        else
+          # Current versions of Mastodon incorrectly omit the query string from the (request-target) pseudo-header.
+          # Therefore, temporarily support such incorrect signatures for compatibility.
+          # TODO: remove eventually some time after release of the fixed version
+          "#{Request::REQUEST_TARGET}: #{request.method.downcase} #{request.path}"
+        end
+      when '(created)'
         raise SignatureVerificationError, 'Invalid pseudo-header (created) for rsa-sha256' unless signature_algorithm == 'hs2019'
         raise SignatureVerificationError, 'Pseudo-header (created) used but corresponding argument missing' if signature_params['created'].blank?
 
         "(created): #{signature_params['created']}"
-      elsif signed_header == '(expires)'
+      when '(expires)'
         raise SignatureVerificationError, 'Invalid pseudo-header (expires) for rsa-sha256' unless signature_algorithm == 'hs2019'
         raise SignatureVerificationError, 'Pseudo-header (expires) used but corresponding argument missing' if signature_params['expires'].blank?
 
diff --git a/app/controllers/concerns/two_factor_authentication_concern.rb b/app/controllers/concerns/two_factor_authentication_concern.rb
index 27f2367a8..ade02f04b 100644
--- a/app/controllers/concerns/two_factor_authentication_concern.rb
+++ b/app/controllers/concerns/two_factor_authentication_concern.rb
@@ -65,6 +65,11 @@ module TwoFactorAuthenticationConcern
   end
 
   def authenticate_with_two_factor_via_otp(user)
+    if check_second_factor_rate_limits(user)
+      flash.now[:alert] = I18n.t('users.rate_limited')
+      return prompt_for_two_factor(user)
+    end
+
     if valid_otp_attempt?(user)
       on_authentication_success(user, :otp)
     else
diff --git a/app/helpers/jsonld_helper.rb b/app/helpers/jsonld_helper.rb
index e5787fd47..6fea05884 100644
--- a/app/helpers/jsonld_helper.rb
+++ b/app/helpers/jsonld_helper.rb
@@ -157,7 +157,7 @@ module JsonLdHelper
     end
   end
 
-  def fetch_resource(uri, id, on_behalf_of = nil)
+  def fetch_resource(uri, id, on_behalf_of = nil, request_options: {})
     unless id
       json = fetch_resource_without_id_validation(uri, on_behalf_of)
 
@@ -166,14 +166,14 @@ module JsonLdHelper
       uri = json['id']
     end
 
-    json = fetch_resource_without_id_validation(uri, on_behalf_of)
+    json = fetch_resource_without_id_validation(uri, on_behalf_of, request_options: request_options)
     json.present? && json['id'] == uri ? json : nil
   end
 
-  def fetch_resource_without_id_validation(uri, on_behalf_of = nil, raise_on_temporary_error = false)
+  def fetch_resource_without_id_validation(uri, on_behalf_of = nil, raise_on_temporary_error = false, request_options: {})
     on_behalf_of ||= Account.representative
 
-    build_request(uri, on_behalf_of).perform do |response|
+    build_request(uri, on_behalf_of, options: request_options).perform do |response|
       raise Mastodon::UnexpectedResponseError, response unless response_successful?(response) || response_error_unsalvageable?(response) || !raise_on_temporary_error
 
       body_to_json(response.body_with_limit) if response.code == 200
@@ -206,8 +206,8 @@ module JsonLdHelper
     response.code == 501 || ((400...500).cover?(response.code) && ![401, 408, 429].include?(response.code))
   end
 
-  def build_request(uri, on_behalf_of = nil)
-    Request.new(:get, uri).tap do |request|
+  def build_request(uri, on_behalf_of = nil, options: {})
+    Request.new(:get, uri, **options).tap do |request|
       request.on_behalf_of(on_behalf_of) if on_behalf_of
       request.add_headers('Accept' => 'application/activity+json, application/ld+json')
     end
diff --git a/app/lib/request.rb b/app/lib/request.rb
index 660dc0fa7..f45cacfcd 100644
--- a/app/lib/request.rb
+++ b/app/lib/request.rb
@@ -77,6 +77,7 @@ class Request
     @url         = Addressable::URI.parse(url).normalize
     @http_client = options.delete(:http_client)
     @allow_local = options.delete(:allow_local)
+    @full_path   = options.delete(:with_query_string)
     @options     = options.merge(socket_class: use_proxy? || @allow_local ? ProxySocket : Socket)
     @options     = @options.merge(timeout_class: PerOperationWithDeadline, timeout_options: TIMEOUT)
     @options     = @options.merge(proxy_url) if use_proxy?
@@ -146,7 +147,7 @@ class Request
   private
 
   def set_common_headers!
-    @headers[REQUEST_TARGET]    = "#{@verb} #{@url.path}"
+    @headers[REQUEST_TARGET]    = request_target
     @headers['User-Agent']      = Mastodon::Version.user_agent
     @headers['Host']            = @url.host
     @headers['Date']            = Time.now.utc.httpdate
@@ -157,6 +158,14 @@ class Request
     @headers['Digest'] = "SHA-256=#{Digest::SHA256.base64digest(@options[:body])}"
   end
 
+  def request_target
+    if @url.query.nil? || !@full_path
+      "#{@verb} #{@url.path}"
+    else
+      "#{@verb} #{@url.path}?#{@url.query}"
+    end
+  end
+
   def signature
     algorithm = 'rsa-sha256'
     signature = Base64.strict_encode64(@keypair.sign(OpenSSL::Digest.new('SHA256'), signed_string))
diff --git a/app/lib/status_reach_finder.rb b/app/lib/status_reach_finder.rb
index 36fb0e80f..17e42e3ec 100644
--- a/app/lib/status_reach_finder.rb
+++ b/app/lib/status_reach_finder.rb
@@ -16,28 +16,28 @@ class StatusReachFinder
   private
 
   def reached_account_inboxes
+    Account.where(id: reached_account_ids).inboxes
+  end
+
+  def reached_account_ids
     # When the status is a reblog, there are no interactions with it
     # directly, we assume all interactions are with the original one
 
     if @status.reblog?
-      []
+      [reblog_of_account_id]
     else
-      Account.where(id: reached_account_ids).inboxes
-    end
-  end
-
-  def reached_account_ids
-    [
-      replied_to_account_id,
-      reblog_of_account_id,
-      mentioned_account_ids,
-      reblogs_account_ids,
-      favourites_account_ids,
-      replies_account_ids,
-    ].tap do |arr|
-      arr.flatten!
-      arr.compact!
-      arr.uniq!
+      [
+        replied_to_account_id,
+        reblog_of_account_id,
+        mentioned_account_ids,
+        reblogs_account_ids,
+        favourites_account_ids,
+        replies_account_ids,
+      ].tap do |arr|
+        arr.flatten!
+        arr.compact!
+        arr.uniq!
+      end
     end
   end
 
diff --git a/app/models/account.rb b/app/models/account.rb
index 31d3fa69c..b69ee0fb0 100644
--- a/app/models/account.rb
+++ b/app/models/account.rb
@@ -112,7 +112,7 @@ class Account < ApplicationRecord
   scope :matches_domain, ->(value) { where(arel_table[:domain].matches("%#{value}%")) }
   scope :without_unapproved, -> { left_outer_joins(:user).remote.or(left_outer_joins(:user).merge(User.approved.confirmed)) }
   scope :searchable, -> { without_unapproved.without_suspended.where(moved_to_account_id: nil) }
-  scope :discoverable, -> { searchable.without_silenced.where(discoverable: true).left_outer_joins(:account_stat) }
+  scope :discoverable, -> { searchable.without_silenced.where(discoverable: true).joins(:account_stat) }
   scope :followable_by, ->(account) { joins(arel_table.join(Follow.arel_table, Arel::Nodes::OuterJoin).on(arel_table[:id].eq(Follow.arel_table[:target_account_id]).and(Follow.arel_table[:account_id].eq(account.id))).join_sources).where(Follow.arel_table[:id].eq(nil)).joins(arel_table.join(FollowRequest.arel_table, Arel::Nodes::OuterJoin).on(arel_table[:id].eq(FollowRequest.arel_table[:target_account_id]).and(FollowRequest.arel_table[:account_id].eq(account.id))).join_sources).where(FollowRequest.arel_table[:id].eq(nil)) }
   scope :by_recent_status, -> { includes(:account_stat).merge(AccountStat.order('last_status_at DESC NULLS LAST')).references(:account_stat) }
   scope :by_recent_sign_in, -> { order(Arel.sql('users.current_sign_in_at DESC NULLS LAST')) }
diff --git a/app/services/activitypub/fetch_featured_collection_service.rb b/app/services/activitypub/fetch_featured_collection_service.rb
index 1208820df..03c5448e4 100644
--- a/app/services/activitypub/fetch_featured_collection_service.rb
+++ b/app/services/activitypub/fetch_featured_collection_service.rb
@@ -23,9 +23,9 @@ class ActivityPub::FetchFeaturedCollectionService < BaseService
 
     case collection['type']
     when 'Collection', 'CollectionPage'
-      collection['items']
+      as_array(collection['items'])
     when 'OrderedCollection', 'OrderedCollectionPage'
-      collection['orderedItems']
+      as_array(collection['orderedItems'])
     end
   end
 
diff --git a/app/services/activitypub/fetch_replies_service.rb b/app/services/activitypub/fetch_replies_service.rb
index 18a27e851..d3f39f3bc 100644
--- a/app/services/activitypub/fetch_replies_service.rb
+++ b/app/services/activitypub/fetch_replies_service.rb
@@ -26,9 +26,9 @@ class ActivityPub::FetchRepliesService < BaseService
 
     case collection['type']
     when 'Collection', 'CollectionPage'
-      collection['items']
+      as_array(collection['items'])
     when 'OrderedCollection', 'OrderedCollectionPage'
-      collection['orderedItems']
+      as_array(collection['orderedItems'])
     end
   end
 
@@ -36,7 +36,21 @@ class ActivityPub::FetchRepliesService < BaseService
     return collection_or_uri if collection_or_uri.is_a?(Hash)
     return unless @allow_synchronous_requests
     return if invalid_origin?(collection_or_uri)
-    fetch_resource_without_id_validation(collection_or_uri, nil, true)
+
+    # NOTE: For backward compatibility reasons, Mastodon signs outgoing
+    # queries incorrectly by default.
+    #
+    # While this is relevant for all URLs with query strings, this is
+    # the only code path where this happens in practice.
+    #
+    # Therefore, retry with correct signatures if this fails.
+    begin
+      fetch_resource_without_id_validation(collection_or_uri, nil, true)
+    rescue Mastodon::UnexpectedResponseError => e
+      raise unless e.response && e.response.code == 401 && Addressable::URI.parse(collection_or_uri).query.present?
+
+      fetch_resource_without_id_validation(collection_or_uri, nil, true, request_options: { with_query_string: true })
+    end
   end
 
   def filtered_replies
diff --git a/app/services/activitypub/synchronize_followers_service.rb b/app/services/activitypub/synchronize_followers_service.rb
index 93cd60253..384fcc525 100644
--- a/app/services/activitypub/synchronize_followers_service.rb
+++ b/app/services/activitypub/synchronize_followers_service.rb
@@ -59,9 +59,9 @@ class ActivityPub::SynchronizeFollowersService < BaseService
 
     case collection['type']
     when 'Collection', 'CollectionPage'
-      collection['items']
+      as_array(collection['items'])
     when 'OrderedCollection', 'OrderedCollectionPage'
-      collection['orderedItems']
+      as_array(collection['orderedItems'])
     end
   end
 
diff --git a/app/services/fetch_oembed_service.rb b/app/services/fetch_oembed_service.rb
index 9851ac098..4c42c8da2 100644
--- a/app/services/fetch_oembed_service.rb
+++ b/app/services/fetch_oembed_service.rb
@@ -100,7 +100,7 @@ class FetchOEmbedService
   end
 
   def validate(oembed)
-    oembed if oembed[:version].to_s == '1.0' && oembed[:type].present?
+    oembed if oembed.present? && oembed[:version].to_s == '1.0' && oembed[:type].present?
   end
 
   def html
diff --git a/app/services/keys/query_service.rb b/app/services/keys/query_service.rb
index 404854c9f..8d727b094 100644
--- a/app/services/keys/query_service.rb
+++ b/app/services/keys/query_service.rb
@@ -69,7 +69,7 @@ class Keys::QueryService < BaseService
 
     return if json['items'].blank?
 
-    @devices = json['items'].map do |device|
+    @devices = as_array(json['items']).map do |device|
       Device.new(device_id: device['id'], name: device['name'], identity_key: device.dig('identityKey', 'publicKeyBase64'), fingerprint_key: device.dig('fingerprintKey', 'publicKeyBase64'), claim_url: device['claim'])
     end
   rescue HTTP::Error, OpenSSL::SSL::SSLError, Mastodon::Error => e
diff --git a/app/services/reblog_service.rb b/app/services/reblog_service.rb
index 7d2981709..3f0594f39 100644
--- a/app/services/reblog_service.rb
+++ b/app/services/reblog_service.rb
@@ -45,11 +45,7 @@ class ReblogService < BaseService
   def create_notification(reblog)
     reblogged_status = reblog.reblog
 
-    if reblogged_status.account.local?
-      LocalNotificationWorker.perform_async(reblogged_status.account_id, reblog.id, reblog.class.name, 'reblog')
-    elsif reblogged_status.account.activitypub? && !reblogged_status.account.following?(reblog.account)
-      ActivityPub::DeliveryWorker.perform_async(build_json(reblog), reblog.account_id, reblogged_status.account.inbox_url)
-    end
+    LocalNotificationWorker.perform_async(reblogged_status.account_id, reblog.id, reblog.class.name, 'reblog') if reblogged_status.account.local?
   end
 
   def bump_potential_friendship(account, reblog)
diff --git a/app/workers/link_crawl_worker.rb b/app/workers/link_crawl_worker.rb
index b3d8aa264..c63af1e43 100644
--- a/app/workers/link_crawl_worker.rb
+++ b/app/workers/link_crawl_worker.rb
@@ -7,7 +7,7 @@ class LinkCrawlWorker
 
   def perform(status_id)
     FetchLinkCardService.new.call(Status.find(status_id))
-  rescue ActiveRecord::RecordNotFound
+  rescue ActiveRecord::RecordNotFound, ActiveRecord::RecordNotUnique
     true
   end
 end
diff --git a/config/locales/en.yml b/config/locales/en.yml
index e9a7ea175..32434ff25 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -1684,6 +1684,7 @@ en:
     follow_limit_reached: You cannot follow more than %{limit} people
     invalid_otp_token: Invalid two-factor code
     otp_lost_help_html: If you lost access to both, you may get in touch with %{email}
+    rate_limited: Too many authentication attempts, try again later.
     seamless_external_login: You are logged in via an external service, so password and e-mail settings are not available.
     signed_in_as: 'Signed in as:'
   verification:
diff --git a/docker-compose.yml b/docker-compose.yml
index 877edcb4f..ae8f9949a 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -56,7 +56,7 @@ services:
 
   web:
     build: .
-    image: ghcr.io/mastodon/mastodon:v4.1.11
+    image: ghcr.io/mastodon/mastodon:v4.1.12
     restart: always
     env_file: .env.production
     command: bash -c "rm -f /mastodon/tmp/pids/server.pid; bundle exec rails s -p 3000"
@@ -77,7 +77,7 @@ services:
 
   streaming:
     build: .
-    image: ghcr.io/mastodon/mastodon:v4.1.11
+    image: ghcr.io/mastodon/mastodon:v4.1.12
     restart: always
     env_file: .env.production
     command: node ./streaming
@@ -95,7 +95,7 @@ services:
 
   sidekiq:
     build: .
-    image: ghcr.io/mastodon/mastodon:v4.1.11
+    image: ghcr.io/mastodon/mastodon:v4.1.12
     restart: always
     env_file: .env.production
     command: bundle exec sidekiq
diff --git a/lib/mastodon/version.rb b/lib/mastodon/version.rb
index 466622a0c..3ed318de7 100644
--- a/lib/mastodon/version.rb
+++ b/lib/mastodon/version.rb
@@ -13,7 +13,7 @@ module Mastodon
     end
 
     def patch
-      11
+      12
     end
 
     def flags
diff --git a/lib/paperclip/response_with_limit_adapter.rb b/lib/paperclip/response_with_limit_adapter.rb
index deb89717a..ff7a938ab 100644
--- a/lib/paperclip/response_with_limit_adapter.rb
+++ b/lib/paperclip/response_with_limit_adapter.rb
@@ -16,7 +16,7 @@ module Paperclip
     private
 
     def cache_current_values
-      @original_filename = filename_from_content_disposition.presence || filename_from_path.presence || 'data'
+      @original_filename = truncated_filename
       @tempfile = copy_to_tempfile(@target)
       @content_type = ContentTypeDetector.new(@tempfile.path).detect
       @size = File.size(@tempfile)
@@ -43,6 +43,13 @@ module Paperclip
       source.response.connection.close
     end
 
+    def truncated_filename
+      filename = filename_from_content_disposition.presence || filename_from_path.presence || 'data'
+      extension = File.extname(filename)
+      basename = File.basename(filename, extension)
+      [basename[...20], extension[..4]].compact_blank.join
+    end
+
     def filename_from_content_disposition
       disposition = @target.response.headers['content-disposition']
       disposition&.match(/filename="([^"]*)"/)&.captures&.first
diff --git a/spec/controllers/api/v1/streaming_controller_spec.rb b/spec/controllers/api/v1/streaming_controller_spec.rb
index 4ab409a54..96062ead7 100644
--- a/spec/controllers/api/v1/streaming_controller_spec.rb
+++ b/spec/controllers/api/v1/streaming_controller_spec.rb
@@ -5,7 +5,7 @@ require 'rails_helper'
 describe Api::V1::StreamingController do
   around(:each) do |example|
     before = Rails.configuration.x.streaming_api_base_url
-    Rails.configuration.x.streaming_api_base_url = Rails.configuration.x.web_domain
+    Rails.configuration.x.streaming_api_base_url = "wss://#{Rails.configuration.x.web_domain}"
     example.run
     Rails.configuration.x.streaming_api_base_url = before
   end
diff --git a/spec/controllers/auth/sessions_controller_spec.rb b/spec/controllers/auth/sessions_controller_spec.rb
index d3db7aa1a..0941e2cb3 100644
--- a/spec/controllers/auth/sessions_controller_spec.rb
+++ b/spec/controllers/auth/sessions_controller_spec.rb
@@ -262,7 +262,27 @@ RSpec.describe Auth::SessionsController, type: :controller do
           end
         end
 
-        context 'using a valid OTP' do
+        context 'when repeatedly using an invalid TOTP code before using a valid code' do
+          before do
+            stub_const('Auth::SessionsController::MAX_2FA_ATTEMPTS_PER_HOUR', 2)
+          end
+
+          it 'does not log the user in' do
+            # Travel to the beginning of an hour to avoid crossing rate-limit buckets
+            travel_to '2023-12-20T10:00:00Z'
+
+            Auth::SessionsController::MAX_2FA_ATTEMPTS_PER_HOUR.times do
+              post :create, params: { user: { otp_attempt: '1234' } }, session: { attempt_user_id: user.id, attempt_user_updated_at: user.updated_at.to_s }
+              expect(controller.current_user).to be_nil
+            end
+
+            post :create, params: { user: { otp_attempt: user.current_otp } }, session: { attempt_user_id: user.id, attempt_user_updated_at: user.updated_at.to_s }
+            expect(controller.current_user).to be_nil
+            expect(flash[:alert]).to match I18n.t('users.rate_limited')
+          end
+        end
+
+        context 'when using a valid OTP' do
           before do
             post :create, params: { user: { otp_attempt: user.current_otp } }, session: { attempt_user_id: user.id, attempt_user_updated_at: user.updated_at.to_s }
           end
diff --git a/spec/controllers/concerns/signature_verification_spec.rb b/spec/controllers/concerns/signature_verification_spec.rb
deleted file mode 100644
index 13655f313..000000000
--- a/spec/controllers/concerns/signature_verification_spec.rb
+++ /dev/null
@@ -1,303 +0,0 @@
-# frozen_string_literal: true
-
-require 'rails_helper'
-
-describe ApplicationController, type: :controller do
-  class WrappedActor
-    attr_reader :wrapped_account
-
-    def initialize(wrapped_account)
-      @wrapped_account = wrapped_account
-    end
-
-    delegate :uri, :keypair, to: :wrapped_account
-  end
-
-  controller do
-    include SignatureVerification
-
-    before_action :require_actor_signature!, only: [:signature_required]
-
-    def success
-      head 200
-    end
-
-    def alternative_success
-      head 200
-    end
-
-    def signature_required
-      head 200
-    end
-  end
-
-  before do
-    routes.draw do
-      match via: [:get, :post], 'success' => 'anonymous#success'
-      match via: [:get, :post], 'signature_required' => 'anonymous#signature_required'
-    end
-  end
-
-  context 'without signature header' do
-    before do
-      get :success
-    end
-
-    describe '#signed_request?' do
-      it 'returns false' do
-        expect(controller.signed_request?).to be false
-      end
-    end
-
-    describe '#signed_request_account' do
-      it 'returns nil' do
-        expect(controller.signed_request_account).to be_nil
-      end
-    end
-  end
-
-  context 'with signature header' do
-    let!(:author) { Fabricate(:account, domain: 'example.com', uri: 'https://example.com/actor') }
-
-    context 'without body' do
-      before do
-        get :success
-
-        fake_request = Request.new(:get, request.url)
-        fake_request.on_behalf_of(author)
-
-        request.headers.merge!(fake_request.headers)
-      end
-
-      describe '#signed_request?' do
-        it 'returns true' do
-          expect(controller.signed_request?).to be true
-        end
-      end
-
-      describe '#signed_request_account' do
-        it 'returns an account' do
-          expect(controller.signed_request_account).to eq author
-        end
-
-        it 'returns nil when path does not match' do
-          request.path = '/alternative-path'
-          expect(controller.signed_request_account).to be_nil
-        end
-
-        it 'returns nil when method does not match' do
-          post :success
-          expect(controller.signed_request_account).to be_nil
-        end
-      end
-    end
-
-    context 'with a valid actor that is not an Account' do
-      let(:actor) { WrappedActor.new(author) }
-
-      before do
-        get :success
-
-        fake_request = Request.new(:get, request.url)
-        fake_request.on_behalf_of(author)
-
-        request.headers.merge!(fake_request.headers)
-
-        allow(ActivityPub::TagManager.instance).to receive(:uri_to_actor).with(anything) do
-          actor
-        end
-      end
-
-      describe '#signed_request?' do
-        it 'returns true' do
-          expect(controller.signed_request?).to be true
-        end
-      end
-
-      describe '#signed_request_account' do
-        it 'returns nil' do
-          expect(controller.signed_request_account).to be_nil
-        end
-      end
-
-      describe '#signed_request_actor' do
-        it 'returns the expected actor' do
-          expect(controller.signed_request_actor).to eq actor
-        end
-      end
-    end
-
-    context 'with request with unparseable Date header' do
-      before do
-        get :success
-
-        fake_request = Request.new(:get, request.url)
-        fake_request.add_headers({ 'Date' => 'wrong date' })
-        fake_request.on_behalf_of(author)
-
-        request.headers.merge!(fake_request.headers)
-      end
-
-      describe '#signed_request?' do
-        it 'returns true' do
-          expect(controller.signed_request?).to be true
-        end
-      end
-
-      describe '#signed_request_account' do
-        it 'returns nil' do
-          expect(controller.signed_request_account).to be_nil
-        end
-      end
-
-      describe '#signature_verification_failure_reason' do
-        it 'contains an error description' do
-          controller.signed_request_account
-          expect(controller.signature_verification_failure_reason[:error]).to eq 'Invalid Date header: not RFC 2616 compliant date: "wrong date"'
-        end
-      end
-    end
-
-    context 'with request older than a day' do
-      before do
-        get :success
-
-        fake_request = Request.new(:get, request.url)
-        fake_request.add_headers({ 'Date' => 2.days.ago.utc.httpdate })
-        fake_request.on_behalf_of(author)
-
-        request.headers.merge!(fake_request.headers)
-      end
-
-      describe '#signed_request?' do
-        it 'returns true' do
-          expect(controller.signed_request?).to be true
-        end
-      end
-
-      describe '#signed_request_account' do
-        it 'returns nil' do
-          expect(controller.signed_request_account).to be_nil
-        end
-      end
-
-      describe '#signature_verification_failure_reason' do
-        it 'contains an error description' do
-          controller.signed_request_account
-          expect(controller.signature_verification_failure_reason[:error]).to eq 'Signed request date outside acceptable time window'
-        end
-      end
-    end
-
-    context 'with inaccessible key' do
-      before do
-        get :success
-
-        author = Fabricate(:account, domain: 'localhost:5000', uri: 'http://localhost:5000/actor')
-        fake_request = Request.new(:get, request.url)
-        fake_request.on_behalf_of(author)
-        author.destroy
-
-        request.headers.merge!(fake_request.headers)
-
-        stub_request(:get, 'http://localhost:5000/actor#main-key').to_raise(Mastodon::HostValidationError)
-      end
-
-      describe '#signed_request?' do
-        it 'returns true' do
-          expect(controller.signed_request?).to be true
-        end
-      end
-
-      describe '#signed_request_account' do
-        it 'returns nil' do
-          expect(controller.signed_request_account).to be_nil
-        end
-      end
-    end
-
-    context 'with body' do
-      before do
-        allow(controller).to receive(:actor_refresh_key!).and_return(author)
-        post :success, body: 'Hello world'
-
-        fake_request = Request.new(:post, request.url, body: 'Hello world')
-        fake_request.on_behalf_of(author)
-
-        request.headers.merge!(fake_request.headers)
-      end
-
-      describe '#signed_request?' do
-        it 'returns true' do
-          expect(controller.signed_request?).to be true
-        end
-      end
-
-      describe '#signed_request_account' do
-        it 'returns an account' do
-          expect(controller.signed_request_account).to eq author
-        end
-      end
-
-      context 'when path does not match' do
-        before do
-          request.path = '/alternative-path'
-        end
-
-        describe '#signed_request_account' do
-          it 'returns nil' do
-            expect(controller.signed_request_account).to be_nil
-          end
-        end
-
-        describe '#signature_verification_failure_reason' do
-          it 'contains an error description' do
-            controller.signed_request_account
-            expect(controller.signature_verification_failure_reason[:error]).to include('using rsa-sha256 (RSASSA-PKCS1-v1_5 with SHA-256)')
-            expect(controller.signature_verification_failure_reason[:signed_string]).to include("(request-target): post /alternative-path\n")
-          end
-        end
-      end
-
-      context 'when method does not match' do
-        before do
-          get :success
-        end
-
-        describe '#signed_request_account' do
-          it 'returns nil' do
-            expect(controller.signed_request_account).to be_nil
-          end
-        end
-      end
-
-      context 'when body has been tampered' do
-        before do
-          post :success, body: 'doo doo doo'
-        end
-
-        describe '#signed_request_account' do
-          it 'returns nil when body has been tampered' do
-            expect(controller.signed_request_account).to be_nil
-          end
-        end
-      end
-    end
-  end
-
-  context 'when a signature is required' do
-    before do
-      get :signature_required
-    end
-
-    context 'without signature header' do
-      it 'returns HTTP 401' do
-        expect(response).to have_http_status(401)
-      end
-
-      it 'returns an error' do
-        expect(Oj.load(response.body)['error']).to eq 'Request not signed'
-      end
-    end
-  end
-end
diff --git a/spec/lib/activitypub/tag_manager_spec.rb b/spec/lib/activitypub/tag_manager_spec.rb
index 606a1de2e..2afdeba7d 100644
--- a/spec/lib/activitypub/tag_manager_spec.rb
+++ b/spec/lib/activitypub/tag_manager_spec.rb
@@ -110,6 +110,14 @@ RSpec.describe ActivityPub::TagManager do
       expect(subject.cc(status)).to include(subject.uri_for(foo))
       expect(subject.cc(status)).to_not include(subject.uri_for(alice))
     end
+
+    it 'returns poster of reblogged post, if reblog' do
+      bob    = Fabricate(:account, username: 'bob', domain: 'example.com', inbox_url: 'http://example.com/bob')
+      alice  = Fabricate(:account, username: 'alice')
+      status = Fabricate(:status, visibility: :public, account: bob)
+      reblog = Fabricate(:status, visibility: :public, account: alice, reblog: status)
+      expect(subject.cc(reblog)).to include(subject.uri_for(bob))
+    end
   end
 
   describe '#local_uri?' do
diff --git a/spec/requests/api/v1/directories_spec.rb b/spec/requests/api/v1/directories_spec.rb
new file mode 100644
index 000000000..0a1864d13
--- /dev/null
+++ b/spec/requests/api/v1/directories_spec.rb
@@ -0,0 +1,139 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe 'Directories API' do
+  let(:user)    { Fabricate(:user, confirmed_at: nil) }
+  let(:token)   { Fabricate(:accessible_access_token, resource_owner_id: user.id, scopes: scopes) }
+  let(:scopes)  { 'read:follows' }
+  let(:headers) { { 'Authorization' => "Bearer #{token.token}" } }
+
+  describe 'GET /api/v1/directories' do
+    context 'with no params' do
+      before do
+        local_unconfirmed_account = Fabricate(
+          :account,
+          domain: nil,
+          user: Fabricate(:user, confirmed_at: nil, approved: true),
+          username: 'local_unconfirmed'
+        )
+        local_unconfirmed_account.create_account_stat!
+
+        local_unapproved_account = Fabricate(
+          :account,
+          domain: nil,
+          user: Fabricate(:user, confirmed_at: 10.days.ago),
+          username: 'local_unapproved'
+        )
+        local_unapproved_account.create_account_stat!
+        local_unapproved_account.user.update(approved: false)
+
+        local_undiscoverable_account = Fabricate(
+          :account,
+          domain: nil,
+          user: Fabricate(:user, confirmed_at: 10.days.ago, approved: true),
+          discoverable: false,
+          username: 'local_undiscoverable'
+        )
+        local_undiscoverable_account.create_account_stat!
+
+        excluded_from_timeline_account = Fabricate(
+          :account,
+          domain: 'host.example',
+          discoverable: true,
+          username: 'remote_excluded_from_timeline'
+        )
+        excluded_from_timeline_account.create_account_stat!
+        Fabricate(:block, account: user.account, target_account: excluded_from_timeline_account)
+
+        domain_blocked_account = Fabricate(
+          :account,
+          domain: 'test.example',
+          discoverable: true,
+          username: 'remote_domain_blocked'
+        )
+        domain_blocked_account.create_account_stat!
+        Fabricate(:account_domain_block, account: user.account, domain: 'test.example')
+
+        local_discoverable_account.create_account_stat!
+        eligible_remote_account.create_account_stat!
+      end
+
+      let(:local_discoverable_account) do
+        Fabricate(
+          :account,
+          domain: nil,
+          user: Fabricate(:user, confirmed_at: 10.days.ago, approved: true),
+          discoverable: true,
+          username: 'local_discoverable'
+        )
+      end
+
+      let(:eligible_remote_account) do
+        Fabricate(
+          :account,
+          domain: 'host.example',
+          discoverable: true,
+          username: 'eligible_remote'
+        )
+      end
+
+      it 'returns the local discoverable account and the remote discoverable account' do
+        get '/api/v1/directory', headers: headers
+
+        expect(response).to have_http_status(200)
+        expect(body_as_json.size).to eq(2)
+        expect(body_as_json.pluck(:id)).to contain_exactly(eligible_remote_account.id.to_s, local_discoverable_account.id.to_s)
+      end
+    end
+
+    context 'when asking for local accounts only' do
+      let(:user) { Fabricate(:user, confirmed_at: 10.days.ago, approved: true) }
+      let(:local_account) { Fabricate(:account, domain: nil, user: user) }
+      let(:remote_account) { Fabricate(:account, domain: 'host.example') }
+
+      before do
+        local_account.create_account_stat!
+        remote_account.create_account_stat!
+      end
+
+      it 'returns only the local accounts' do
+        get '/api/v1/directory', headers: headers, params: { local: '1' }
+
+        expect(response).to have_http_status(200)
+        expect(body_as_json.size).to eq(1)
+        expect(body_as_json.first[:id]).to include(local_account.id.to_s)
+        expect(response.body).to_not include(remote_account.id.to_s)
+      end
+    end
+
+    context 'when ordered by active' do
+      it 'returns accounts in order of most recent status activity' do
+        old_stat = Fabricate(:account_stat, last_status_at: 1.day.ago)
+        new_stat = Fabricate(:account_stat, last_status_at: 1.minute.ago)
+
+        get '/api/v1/directory', headers: headers, params: { order: 'active' }
+
+        expect(response).to have_http_status(200)
+        expect(body_as_json.size).to eq(2)
+        expect(body_as_json.first[:id]).to include(new_stat.account_id.to_s)
+        expect(body_as_json.second[:id]).to include(old_stat.account_id.to_s)
+      end
+    end
+
+    context 'when ordered by new' do
+      it 'returns accounts in order of creation' do
+        account_old = Fabricate(:account_stat).account
+        travel_to 10.seconds.from_now
+        account_new = Fabricate(:account_stat).account
+
+        get '/api/v1/directory', headers: headers, params: { order: 'new' }
+
+        expect(response).to have_http_status(200)
+        expect(body_as_json.size).to eq(2)
+        expect(body_as_json.first[:id]).to include(account_new.id.to_s)
+        expect(body_as_json.second[:id]).to include(account_old.id.to_s)
+      end
+    end
+  end
+end
diff --git a/spec/requests/signature_verification_spec.rb b/spec/requests/signature_verification_spec.rb
new file mode 100644
index 000000000..401828c4a
--- /dev/null
+++ b/spec/requests/signature_verification_spec.rb
@@ -0,0 +1,398 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe 'signature verification concern' do
+  before do
+    stub_tests_controller
+
+    # Signature checking is time-dependent, so travel to a fixed date
+    travel_to '2023-12-20T10:00:00Z'
+  end
+
+  after { Rails.application.reload_routes! }
+
+  # Include the private key so the tests can be easily adjusted and reviewed
+  let(:actor_keypair) do
+    OpenSSL::PKey.read(<<~PEM_TEXT)
+      -----BEGIN RSA PRIVATE KEY-----
+      MIIEowIBAAKCAQEAqIAYvNFGbZ5g4iiK6feSdXD4bDStFM58A7tHycYXaYtzZQpI
+      eHXAmaXuZzXIwtrP4N0gIk8JNwZvXj2UPS+S07t0V9wNK94he01LV5EMz/GN4eNn
+      FmDL64HIEuKLvV8TvgjbUPRD6Y5X0UpKi2ZIFLSb96Q5w0Z/k7ntpVKV52y8kz5F
+      jr/O/0JuHryZe0yItzJh8kzFfeMf0EXzfSnaKvT7P9jhgC6uTre+jXyvVZjiHDrn
+      qvvucdI3I7DRfXo1OqARBrLjy+TdseUAjNYJ+OuPRI1URIWQI01DCHqcohVu9+Ar
+      +BiCjFp3ua+XMuJvrvbD61d1Fvig/9nbBRR+8QIDAQABAoIBAAgySHnFWI6gItR3
+      fkfiqIm80cHCN3Xk1C6iiVu+3oBOZbHpW9R7vl9e/WOA/9O+LPjiSsQOegtWnVvd
+      RRjrl7Hj20VDlZKv5Mssm6zOGAxksrcVbqwdj+fUJaNJCL0AyyseH0x/IE9T8rDC
+      I1GH+3tB3JkhkIN/qjipdX5ab8MswEPu8IC4ViTpdBgWYY/xBcAHPw4xuL0tcwzh
+      FBlf4DqoEVQo8GdK5GAJ2Ny0S4xbXHUURzx/R4y4CCts7niAiLGqd9jmLU1kUTMk
+      QcXfQYK6l+unLc7wDYAz7sFEHh04M48VjWwiIZJnlCqmQbLda7uhhu8zkF1DqZTu
+      ulWDGQECgYEA0TIAc8BQBVab979DHEEmMdgqBwxLY3OIAk0b+r50h7VBGWCDPRsC
+      STD73fQY3lNet/7/jgSGwwAlAJ5PpMXxXiZAE3bUwPmHzgF7pvIOOLhA8O07tHSO
+      L2mvQe6NPzjZ+6iAO2U9PkClxcvGvPx2OBvisfHqZLmxC9PIVxzruQECgYEAzjM6
+      BTUXa6T/qHvLFbN699BXsUOGmHBGaLRapFDBfVvgZrwqYQcZpBBhesLdGTGSqwE7
+      gWsITPIJ+Ldo+38oGYyVys+w/V67q6ud7hgSDTW3hSvm+GboCjk6gzxlt9hQ0t9X
+      8vfDOYhEXvVUJNv3mYO60ENqQhILO4bQ0zi+VfECgYBb/nUccfG+pzunU0Cb6Dp3
+      qOuydcGhVmj1OhuXxLFSDG84Tazo7juvHA9mp7VX76mzmDuhpHPuxN2AzB2SBEoE
+      cSW0aYld413JRfWukLuYTc6hJHIhBTCRwRQFFnae2s1hUdQySm8INT2xIc+fxBXo
+      zrp+Ljg5Wz90SAnN5TX0AQKBgDaatDOq0o/r+tPYLHiLtfWoE4Dau+rkWJDjqdk3
+      lXWn/e3WyHY3Vh/vQpEqxzgju45TXjmwaVtPATr+/usSykCxzP0PMPR3wMT+Rm1F
+      rIoY/odij+CaB7qlWwxj0x/zRbwB7x1lZSp4HnrzBpxYL+JUUwVRxPLIKndSBTza
+      GvVRAoGBAIVBcNcRQYF4fvZjDKAb4fdBsEuHmycqtRCsnkGOz6ebbEQznSaZ0tZE
+      +JuouZaGjyp8uPjNGD5D7mIGbyoZ3KyG4mTXNxDAGBso1hrNDKGBOrGaPhZx8LgO
+      4VXJ+ybXrATf4jr8ccZYsZdFpOphPzz+j55Mqg5vac5P1XjmsGTb
+      -----END RSA PRIVATE KEY-----
+    PEM_TEXT
+  end
+
+  context 'without a Signature header' do
+    it 'does not treat the request as signed' do
+      get '/activitypub/success'
+
+      expect(response).to have_http_status(200)
+      expect(body_as_json).to match(
+        signed_request: false,
+        signature_actor_id: nil,
+        error: 'Request not signed'
+      )
+    end
+
+    context 'when a signature is required' do
+      it 'returns http unauthorized with appropriate error' do
+        get '/activitypub/signature_required'
+
+        expect(response).to have_http_status(401)
+        expect(body_as_json).to match(
+          error: 'Request not signed'
+        )
+      end
+    end
+  end
+
+  context 'with an HTTP Signature from a known account' do
+    let!(:actor) { Fabricate(:account, domain: 'remote.domain', uri: 'https://remote.domain/users/bob', private_key: nil, public_key: actor_keypair.public_key.to_pem) }
+
+    context 'with a valid signature on a GET request' do
+      let(:signature_header) do
+        'keyId="https://remote.domain/users/bob#main-key",algorithm="rsa-sha256",headers="date host (request-target)",signature="Z8ilar3J7bOwqZkMp7sL8sRs4B1FT+UorbmvWoE+A5UeoOJ3KBcUmbsh+k3wQwbP5gMNUrra9rEWabpasZGphLsbDxfbsWL3Cf0PllAc7c1c7AFEwnewtExI83/qqgEkfWc2z7UDutXc2NfgAx89Ox8DXU/fA2GG0jILjB6UpFyNugkY9rg6oI31UnvfVi3R7sr3/x8Ea3I9thPvqI2byF6cojknSpDAwYzeKdngX3TAQEGzFHz3SDWwyp3jeMWfwvVVbM38FxhvAnSumw7YwWW4L7M7h4M68isLimoT3yfCn2ucBVL5Dz8koBpYf/40w7QidClAwCafZQFC29yDOg=="' # rubocop:disable Layout/LineLength
+      end
+
+      it 'successfuly verifies signature', :aggregate_failures do
+        expect(signature_header).to eq build_signature_string(actor_keypair, 'https://remote.domain/users/bob#main-key', 'get /activitypub/success', { 'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT', 'Host' => 'www.example.com' })
+
+        get '/activitypub/success', headers: {
+          'Host' => 'www.example.com',
+          'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT',
+          'Signature' => signature_header,
+        }
+
+        expect(response).to have_http_status(200)
+        expect(body_as_json).to match(
+          signed_request: true,
+          signature_actor_id: actor.id.to_s
+        )
+      end
+    end
+
+    context 'with a valid signature on a GET request that has a query string' do
+      let(:signature_header) do
+        'keyId="https://remote.domain/users/bob#main-key",algorithm="rsa-sha256",headers="date host (request-target)",signature="SDMa4r/DQYMXYxVgYO2yEqGWWUXugKjVuz0I8dniQAk+aunzBaF2aPu+4grBfawAshlx1Xytl8lhb0H2MllEz16/tKY7rUrb70MK0w8ohXgpb0qs3YvQgdj4X24L1x2MnkFfKHR/J+7TBlnivq0HZqXm8EIkPWLv+eQxu8fbowLwHIVvRd/3t6FzvcfsE0UZKkoMEX02542MhwSif6cu7Ec/clsY9qgKahb9JVGOGS1op9Lvg/9y1mc8KCgD83U5IxVygYeYXaVQ6gixA9NgZiTCwEWzHM5ELm7w5hpdLFYxYOHg/3G3fiqJzpzNQAcCD4S4JxfE7hMI0IzVlNLT6A=="' # rubocop:disable Layout/LineLength
+      end
+
+      it 'successfuly verifies signature', :aggregate_failures do
+        expect(signature_header).to eq build_signature_string(actor_keypair, 'https://remote.domain/users/bob#main-key', 'get /activitypub/success?foo=42', { 'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT', 'Host' => 'www.example.com' })
+
+        get '/activitypub/success?foo=42', headers: {
+          'Host' => 'www.example.com',
+          'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT',
+          'Signature' => signature_header,
+        }
+
+        expect(response).to have_http_status(200)
+        expect(body_as_json).to match(
+          signed_request: true,
+          signature_actor_id: actor.id.to_s
+        )
+      end
+    end
+
+    context 'when the query string is missing from the signature verification (compatibility quirk)' do
+      let(:signature_header) do
+        'keyId="https://remote.domain/users/bob#main-key",algorithm="rsa-sha256",headers="date host (request-target)",signature="Z8ilar3J7bOwqZkMp7sL8sRs4B1FT+UorbmvWoE+A5UeoOJ3KBcUmbsh+k3wQwbP5gMNUrra9rEWabpasZGphLsbDxfbsWL3Cf0PllAc7c1c7AFEwnewtExI83/qqgEkfWc2z7UDutXc2NfgAx89Ox8DXU/fA2GG0jILjB6UpFyNugkY9rg6oI31UnvfVi3R7sr3/x8Ea3I9thPvqI2byF6cojknSpDAwYzeKdngX3TAQEGzFHz3SDWwyp3jeMWfwvVVbM38FxhvAnSumw7YwWW4L7M7h4M68isLimoT3yfCn2ucBVL5Dz8koBpYf/40w7QidClAwCafZQFC29yDOg=="' # rubocop:disable Layout/LineLength
+      end
+
+      it 'successfuly verifies signature', :aggregate_failures do
+        expect(signature_header).to eq build_signature_string(actor_keypair, 'https://remote.domain/users/bob#main-key', 'get /activitypub/success', { 'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT', 'Host' => 'www.example.com' })
+
+        get '/activitypub/success?foo=42', headers: {
+          'Host' => 'www.example.com',
+          'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT',
+          'Signature' => signature_header,
+        }
+
+        expect(response).to have_http_status(200)
+        expect(body_as_json).to match(
+          signed_request: true,
+          signature_actor_id: actor.id.to_s
+        )
+      end
+    end
+
+    context 'with mismatching query string' do
+      let(:signature_header) do
+        'keyId="https://remote.domain/users/bob#main-key",algorithm="rsa-sha256",headers="date host (request-target)",signature="SDMa4r/DQYMXYxVgYO2yEqGWWUXugKjVuz0I8dniQAk+aunzBaF2aPu+4grBfawAshlx1Xytl8lhb0H2MllEz16/tKY7rUrb70MK0w8ohXgpb0qs3YvQgdj4X24L1x2MnkFfKHR/J+7TBlnivq0HZqXm8EIkPWLv+eQxu8fbowLwHIVvRd/3t6FzvcfsE0UZKkoMEX02542MhwSif6cu7Ec/clsY9qgKahb9JVGOGS1op9Lvg/9y1mc8KCgD83U5IxVygYeYXaVQ6gixA9NgZiTCwEWzHM5ELm7w5hpdLFYxYOHg/3G3fiqJzpzNQAcCD4S4JxfE7hMI0IzVlNLT6A=="' # rubocop:disable Layout/LineLength
+      end
+
+      it 'fails to verify signature', :aggregate_failures do
+        expect(signature_header).to eq build_signature_string(actor_keypair, 'https://remote.domain/users/bob#main-key', 'get /activitypub/success?foo=42', { 'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT', 'Host' => 'www.example.com' })
+
+        get '/activitypub/success?foo=43', headers: {
+          'Host' => 'www.example.com',
+          'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT',
+          'Signature' => signature_header,
+        }
+
+        expect(body_as_json).to match(
+          signed_request: true,
+          signature_actor_id: nil,
+          error: anything
+        )
+      end
+    end
+
+    context 'with a mismatching path' do
+      it 'fails to verify signature', :aggregate_failures do
+        get '/activitypub/alternative-path', headers: {
+          'Host' => 'www.example.com',
+          'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT',
+          'Signature' => 'keyId="https://remote.domain/users/bob#main-key",algorithm="rsa-sha256",headers="date host (request-target)",signature="Z8ilar3J7bOwqZkMp7sL8sRs4B1FT+UorbmvWoE+A5UeoOJ3KBcUmbsh+k3wQwbP5gMNUrra9rEWabpasZGphLsbDxfbsWL3Cf0PllAc7c1c7AFEwnewtExI83/qqgEkfWc2z7UDutXc2NfgAx89Ox8DXU/fA2GG0jILjB6UpFyNugkY9rg6oI31UnvfVi3R7sr3/x8Ea3I9thPvqI2byF6cojknSpDAwYzeKdngX3TAQEGzFHz3SDWwyp3jeMWfwvVVbM38FxhvAnSumw7YwWW4L7M7h4M68isLimoT3yfCn2ucBVL5Dz8koBpYf/40w7QidClAwCafZQFC29yDOg=="', # rubocop:disable Layout/LineLength
+        }
+
+        expect(body_as_json).to match(
+          signed_request: true,
+          signature_actor_id: nil,
+          error: anything
+        )
+      end
+    end
+
+    context 'with a mismatching method' do
+      it 'fails to verify signature', :aggregate_failures do
+        post '/activitypub/success', headers: {
+          'Host' => 'www.example.com',
+          'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT',
+          'Signature' => 'keyId="https://remote.domain/users/bob#main-key",algorithm="rsa-sha256",headers="date host (request-target)",signature="Z8ilar3J7bOwqZkMp7sL8sRs4B1FT+UorbmvWoE+A5UeoOJ3KBcUmbsh+k3wQwbP5gMNUrra9rEWabpasZGphLsbDxfbsWL3Cf0PllAc7c1c7AFEwnewtExI83/qqgEkfWc2z7UDutXc2NfgAx89Ox8DXU/fA2GG0jILjB6UpFyNugkY9rg6oI31UnvfVi3R7sr3/x8Ea3I9thPvqI2byF6cojknSpDAwYzeKdngX3TAQEGzFHz3SDWwyp3jeMWfwvVVbM38FxhvAnSumw7YwWW4L7M7h4M68isLimoT3yfCn2ucBVL5Dz8koBpYf/40w7QidClAwCafZQFC29yDOg=="', # rubocop:disable Layout/LineLength
+        }
+
+        expect(body_as_json).to match(
+          signed_request: true,
+          signature_actor_id: nil,
+          error: anything
+        )
+      end
+    end
+
+    context 'with an unparsable date' do
+      let(:signature_header) do
+        'keyId="https://remote.domain/users/bob#main-key",algorithm="rsa-sha256",headers="date host (request-target)",signature="d4B7nfx8RJcfdJDu1J//5WzPzK/hgtPkdzZx49lu5QhnE7qdV3lgyVimmhCFrO16bwvzIp9iRMyRLkNFxLiEeVaa1gqeKbldGSnU0B0OMjx7rFBa65vLuzWQOATDitVGiBEYqoK4v0DMuFCz2DtFaA/DIUZ3sty8bZ/Ea3U1nByLOO6MacARA3zhMSI0GNxGqsSmZmG0hPLavB3jIXoE3IDoQabMnC39jrlcO/a8h1iaxBm2WD8TejrImJullgqlJIFpKhIHI3ipQkvTGPlm9dx0y+beM06qBvWaWQcmT09eRIUefVsOAzIhUtS/7FVb/URhZvircIJDa7vtiFcmZQ=="' # rubocop:disable Layout/LineLength
+      end
+
+      it 'fails to verify signature', :aggregate_failures do
+        expect(signature_header).to eq build_signature_string(actor_keypair, 'https://remote.domain/users/bob#main-key', 'get /activitypub/success', { 'Date' => 'wrong date', 'Host' => 'www.example.com' })
+
+        get '/activitypub/success', headers: {
+          'Host' => 'www.example.com',
+          'Date' => 'wrong date',
+          'Signature' => signature_header,
+        }
+
+        expect(body_as_json).to match(
+          signed_request: true,
+          signature_actor_id: nil,
+          error: 'Invalid Date header: not RFC 2616 compliant date: "wrong date"'
+        )
+      end
+    end
+
+    context 'with a request older than a day' do
+      let(:signature_header) do
+        'keyId="https://remote.domain/users/bob#main-key",algorithm="rsa-sha256",headers="date host (request-target)",signature="G1NuJv4zgoZ3B/ZIjzDWZHK4RC+5pYee74q8/LJEMCWXhcnAomcb9YHaqk1QYfQvcBUIXw3UZ3Q9xO8F9y0i8G5mzJHfQ+OgHqCoJk8EmGwsUXJMh5s1S5YFCRt8TT12TmJZz0VMqLq85ubueSYBM7QtUE/FzFIVLvz4RysgXxaXQKzdnM6+gbUEEKdCURpXdQt2NXQhp4MAmZH3+0lQoR6VxdsK0hx0Ji2PNp1nuqFTlYqNWZazVdLBN+9rETLRmvGXknvg9jOxTTppBVWnkAIl26HtLS3wwFVvz4pJzi9OQDOvLziehVyLNbU61hky+oJ215e2HuKSe2hxHNl1MA=="' # rubocop:disable Layout/LineLength
+      end
+
+      it 'fails to verify signature', :aggregate_failures do
+        expect(signature_header).to eq build_signature_string(actor_keypair, 'https://remote.domain/users/bob#main-key', 'get /activitypub/success', { 'Date' => 'Wed, 18 Dec 2023 10:00:00 GMT', 'Host' => 'www.example.com' })
+
+        get '/activitypub/success', headers: {
+          'Host' => 'www.example.com',
+          'Date' => 'Wed, 18 Dec 2023 10:00:00 GMT',
+          'Signature' => signature_header,
+        }
+
+        expect(body_as_json).to match(
+          signed_request: true,
+          signature_actor_id: nil,
+          error: 'Signed request date outside acceptable time window'
+        )
+      end
+    end
+
+    context 'with a valid signature on a POST request' do
+      let(:digest_header) { 'SHA-256=ZOyIygCyaOW6GjVnihtTFtIS9PNmskdyMlNKiuyjfzw=' }
+      let(:signature_header) do
+        'keyId="https://remote.domain/users/bob#main-key",algorithm="rsa-sha256",headers="host date digest (request-target)",signature="gmhMjgMROGElJU3fpehV2acD5kMHeELi8EFP2UPHOdQ54H0r55AxIpji+J3lPe+N2qSb/4H1KXIh6f0lRu8TGSsu12OQmg5hiO8VA9flcA/mh9Lpk+qwlQZIPRqKP9xUEfqD+Z7ti5wPzDKrWAUK/7FIqWgcT/mlqB1R1MGkpMFc/q4CIs2OSNiWgA4K+Kp21oQxzC2kUuYob04gAZ7cyE/FTia5t08uv6lVYFdRsn4XNPn1MsHgFBwBMRG79ng3SyhoG4PrqBEi5q2IdLq3zfre/M6He3wlCpyO2VJNdGVoTIzeZ0Zz8jUscPV3XtWUchpGclLGSaKaq/JyNZeiYQ=="' # rubocop:disable Layout/LineLength
+      end
+
+      it 'successfuly verifies signature', :aggregate_failures do
+        expect(digest_header).to eq digest_value('Hello world')
+        expect(signature_header).to eq build_signature_string(actor_keypair, 'https://remote.domain/users/bob#main-key', 'post /activitypub/success', { 'Host' => 'www.example.com', 'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT', 'Digest' => digest_header })
+
+        post '/activitypub/success', params: 'Hello world', headers: {
+          'Host' => 'www.example.com',
+          'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT',
+          'Digest' => digest_header,
+          'Signature' => signature_header,
+        }
+
+        expect(response).to have_http_status(200)
+        expect(body_as_json).to match(
+          signed_request: true,
+          signature_actor_id: actor.id.to_s
+        )
+      end
+    end
+
+    context 'when the Digest of a POST request is not signed' do
+      let(:digest_header) { 'SHA-256=ZOyIygCyaOW6GjVnihtTFtIS9PNmskdyMlNKiuyjfzw=' }
+      let(:signature_header) do
+        'keyId="https://remote.domain/users/bob#main-key",algorithm="rsa-sha256",headers="host date (request-target)",signature="CPD704CG8aCm8X8qIP8kkkiGp1qwFLk/wMVQHOGP0Txxan8c2DZtg/KK7eN8RG8tHx8br/yS2hJs51x4kXImYukGzNJd7ihE3T8lp+9RI1tCcdobTzr/VcVJHDFySdQkg266GCMijRQRZfNvqlJLiisr817PI+gNVBI5qV+vnVd1XhWCEZ+YSmMe8UqYARXAYNqMykTheojqGpTeTFGPUpTQA2Fmt2BipwIjcFDm2Hpihl2kB0MUS0x3zPmHDuadvzoBbN6m3usPDLgYrpALlh+wDs1dYMntcwdwawRKY1oE1XNtgOSum12wntDq3uYL4gya2iPdcw3c929b4koUzw=="' # rubocop:disable Layout/LineLength
+      end
+
+      it 'fails to verify signature', :aggregate_failures do
+        expect(digest_header).to eq digest_value('Hello world')
+        expect(signature_header).to eq build_signature_string(actor_keypair, 'https://remote.domain/users/bob#main-key', 'post /activitypub/success', { 'Host' => 'www.example.com', 'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT' })
+
+        post '/activitypub/success', params: 'Hello world', headers: {
+          'Host' => 'www.example.com',
+          'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT',
+          'Digest' => digest_header,
+          'Signature' => signature_header,
+        }
+
+        expect(body_as_json).to match(
+          signed_request: true,
+          signature_actor_id: nil,
+          error: 'Mastodon requires the Digest header to be signed when doing a POST request'
+        )
+      end
+    end
+
+    context 'with a tampered body on a POST request' do
+      let(:digest_header) { 'SHA-256=ZOyIygCyaOW6GjVnihtTFtIS9PNmskdyMlNKiuyjfzw=' }
+      let(:signature_header) do
+        'keyId="https://remote.domain/users/bob#main-key",algorithm="rsa-sha256",headers="host date digest (request-target)",signature="gmhMjgMROGElJU3fpehV2acD5kMHeELi8EFP2UPHOdQ54H0r55AxIpji+J3lPe+N2qSb/4H1KXIh6f0lRu8TGSsu12OQmg5hiO8VA9flcA/mh9Lpk+qwlQZIPRqKP9xUEfqD+Z7ti5wPzDKrWAUK/7FIqWgcT/mlqB1R1MGkpMFc/q4CIs2OSNiWgA4K+Kp21oQxzC2kUuYob04gAZ7cyE/FTia5t08uv6lVYFdRsn4XNPn1MsHgFBwBMRG79ng3SyhoG4PrqBEi5q2IdLq3zfre/M6He3wlCpyO2VJNdGVoTIzeZ0Zz8jUscPV3XtWUchpGclLGSaKaq/JyNZeiYQ=="' # rubocop:disable Layout/LineLength
+      end
+
+      it 'fails to verify signature', :aggregate_failures do
+        expect(digest_header).to_not eq digest_value('Hello world!')
+        expect(signature_header).to eq build_signature_string(actor_keypair, 'https://remote.domain/users/bob#main-key', 'post /activitypub/success', { 'Host' => 'www.example.com', 'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT', 'Digest' => digest_header })
+
+        post '/activitypub/success', params: 'Hello world!', headers: {
+          'Host' => 'www.example.com',
+          'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT',
+          'Digest' => 'SHA-256=ZOyIygCyaOW6GjVnihtTFtIS9PNmskdyMlNKiuyjfzw=',
+          'Signature' => signature_header,
+        }
+
+        expect(body_as_json).to match(
+          signed_request: true,
+          signature_actor_id: nil,
+          error: 'Invalid Digest value. Computed SHA-256 digest: wFNeS+K3n/2TKRMFQ2v4iTFOSj+uwF7P/Lt98xrZ5Ro=; given: ZOyIygCyaOW6GjVnihtTFtIS9PNmskdyMlNKiuyjfzw='
+        )
+      end
+    end
+
+    context 'with a tampered path in a POST request' do
+      it 'fails to verify signature', :aggregate_failures do
+        post '/activitypub/alternative-path', params: 'Hello world', headers: {
+          'Host' => 'www.example.com',
+          'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT',
+          'Digest' => 'SHA-256=ZOyIygCyaOW6GjVnihtTFtIS9PNmskdyMlNKiuyjfzw=',
+          'Signature' => 'keyId="https://remote.domain/users/bob#main-key",algorithm="rsa-sha256",headers="host date digest (request-target)",signature="gmhMjgMROGElJU3fpehV2acD5kMHeELi8EFP2UPHOdQ54H0r55AxIpji+J3lPe+N2qSb/4H1KXIh6f0lRu8TGSsu12OQmg5hiO8VA9flcA/mh9Lpk+qwlQZIPRqKP9xUEfqD+Z7ti5wPzDKrWAUK/7FIqWgcT/mlqB1R1MGkpMFc/q4CIs2OSNiWgA4K+Kp21oQxzC2kUuYob04gAZ7cyE/FTia5t08uv6lVYFdRsn4XNPn1MsHgFBwBMRG79ng3SyhoG4PrqBEi5q2IdLq3zfre/M6He3wlCpyO2VJNdGVoTIzeZ0Zz8jUscPV3XtWUchpGclLGSaKaq/JyNZeiYQ=="', # rubocop:disable Layout/LineLength
+        }
+
+        expect(response).to have_http_status(200)
+        expect(body_as_json).to match(
+          signed_request: true,
+          signature_actor_id: nil,
+          error: anything
+        )
+      end
+    end
+  end
+
+  context 'with an inaccessible key' do
+    before do
+      stub_request(:get, 'https://remote.domain/users/alice#main-key').to_return(status: 404)
+    end
+
+    it 'fails to verify signature', :aggregate_failures do
+      get '/activitypub/success', headers: {
+        'Host' => 'www.example.com',
+        'Date' => 'Wed, 20 Dec 2023 10:00:00 GMT',
+        'Signature' => 'keyId="https://remote.domain/users/alice#main-key",algorithm="rsa-sha256",headers="date host (request-target)",signature="Z8ilar3J7bOwqZkMp7sL8sRs4B1FT+UorbmvWoE+A5UeoOJ3KBcUmbsh+k3wQwbP5gMNUrra9rEWabpasZGphLsbDxfbsWL3Cf0PllAc7c1c7AFEwnewtExI83/qqgEkfWc2z7UDutXc2NfgAx89Ox8DXU/fA2GG0jILjB6UpFyNugkY9rg6oI31UnvfVi3R7sr3/x8Ea3I9thPvqI2byF6cojknSpDAwYzeKdngX3TAQEGzFHz3SDWwyp3jeMWfwvVVbM38FxhvAnSumw7YwWW4L7M7h4M68isLimoT3yfCn2ucBVL5Dz8koBpYf/40w7QidClAwCafZQFC29yDOg=="', # rubocop:disable Layout/LineLength
+      }
+
+      expect(body_as_json).to match(
+        signed_request: true,
+        signature_actor_id: nil,
+        error: 'Unable to fetch key JSON at https://remote.domain/users/alice#main-key'
+      )
+    end
+  end
+
+  private
+
+  def stub_tests_controller
+    stub_const('ActivityPub::TestsController', activitypub_tests_controller)
+
+    Rails.application.routes.draw do
+      # NOTE: RouteSet#draw removes all routes, so we need to re-insert one
+      resource :instance_actor, path: 'actor', only: [:show]
+
+      match :via => [:get, :post], '/activitypub/success' => 'activitypub/tests#success'
+      match :via => [:get, :post], '/activitypub/alternative-path' => 'activitypub/tests#alternative_success'
+      match :via => [:get, :post], '/activitypub/signature_required' => 'activitypub/tests#signature_required'
+    end
+  end
+
+  def activitypub_tests_controller
+    Class.new(ApplicationController) do
+      include SignatureVerification
+
+      before_action :require_actor_signature!, only: [:signature_required]
+
+      def success
+        render json: {
+          signed_request: signed_request?,
+          signature_actor_id: signed_request_actor&.id&.to_s,
+        }.merge(signature_verification_failure_reason || {})
+      end
+
+      alias_method :alternative_success, :success
+      alias_method :signature_required, :success
+    end
+  end
+
+  def digest_value(body)
+    "SHA-256=#{Digest::SHA256.base64digest(body)}"
+  end
+
+  def build_signature_string(keypair, key_id, request_target, headers)
+    algorithm = 'rsa-sha256'
+    signed_headers = headers.merge({ '(request-target)' => request_target })
+    signed_string = signed_headers.map { |key, value| "#{key.downcase}: #{value}" }.join("\n")
+    signature = Base64.strict_encode64(keypair.sign(OpenSSL::Digest.new('SHA256'), signed_string))
+
+    "keyId=\"#{key_id}\",algorithm=\"#{algorithm}\",headers=\"#{signed_headers.keys.join(' ').downcase}\",signature=\"#{signature}\""
+  end
+end
diff --git a/spec/services/activitypub/fetch_featured_collection_service_spec.rb b/spec/services/activitypub/fetch_featured_collection_service_spec.rb
index e6336dc1b..e0153225d 100644
--- a/spec/services/activitypub/fetch_featured_collection_service_spec.rb
+++ b/spec/services/activitypub/fetch_featured_collection_service_spec.rb
@@ -97,6 +97,21 @@ RSpec.describe ActivityPub::FetchFeaturedCollectionService, type: :service do
       end
 
       it_behaves_like 'sets pinned posts'
+
+      context 'when there is a single item, with the array compacted away' do
+        let(:items) { 'https://example.com/account/pinned/4' }
+
+        before do
+          stub_request(:get, 'https://example.com/account/pinned/4').to_return(status: 200, body: Oj.dump(status_json_4))
+          subject.call(actor, note: true, hashtag: false)
+        end
+
+        it 'sets expected posts as pinned posts' do
+          expect(actor.pinned_statuses.pluck(:uri)).to contain_exactly(
+            'https://example.com/account/pinned/4'
+          )
+        end
+      end
     end
 
     context 'when the endpoint is a paginated Collection' do
@@ -118,6 +133,21 @@ RSpec.describe ActivityPub::FetchFeaturedCollectionService, type: :service do
       end
 
       it_behaves_like 'sets pinned posts'
+
+      context 'when there is a single item, with the array compacted away' do
+        let(:items) { 'https://example.com/account/pinned/4' }
+
+        before do
+          stub_request(:get, 'https://example.com/account/pinned/4').to_return(status: 200, body: Oj.dump(status_json_4))
+          subject.call(actor, note: true, hashtag: false)
+        end
+
+        it 'sets expected posts as pinned posts' do
+          expect(actor.pinned_statuses.pluck(:uri)).to contain_exactly(
+            'https://example.com/account/pinned/4'
+          )
+        end
+      end
     end
   end
 end
diff --git a/spec/services/activitypub/fetch_replies_service_spec.rb b/spec/services/activitypub/fetch_replies_service_spec.rb
index fe49b18c1..264f305d7 100644
--- a/spec/services/activitypub/fetch_replies_service_spec.rb
+++ b/spec/services/activitypub/fetch_replies_service_spec.rb
@@ -32,6 +32,18 @@ RSpec.describe ActivityPub::FetchRepliesService, type: :service do
 
   describe '#call' do
     context 'when the payload is a Collection with inlined replies' do
+      context 'when there is a single reply, with the array compacted away' do
+        let(:items) { 'http://example.com/self-reply-1' }
+
+        it 'queues the expected worker' do
+          allow(FetchReplyWorker).to receive(:push_bulk)
+
+          subject.call(status, payload)
+
+          expect(FetchReplyWorker).to have_received(:push_bulk).with(['http://example.com/self-reply-1'])
+        end
+      end
+
       context 'when passing the collection itself' do
         it 'spawns workers for up to 5 replies on the same server' do
           expect(FetchReplyWorker).to receive(:push_bulk).with(['http://example.com/self-reply-1', 'http://example.com/self-reply-2', 'http://example.com/self-reply-3', 'http://example.com/self-reply-4', 'http://example.com/self-reply-5'])
diff --git a/spec/services/reblog_service_spec.rb b/spec/services/reblog_service_spec.rb
index c0ae5eedc..24770b4cc 100644
--- a/spec/services/reblog_service_spec.rb
+++ b/spec/services/reblog_service_spec.rb
@@ -69,9 +69,5 @@ RSpec.describe ReblogService, type: :service do
     it 'distributes to followers' do
       expect(ActivityPub::DistributionWorker).to have_received(:perform_async)
     end
-
-    it 'sends an announce activity to the author' do
-      expect(a_request(:post, bob.inbox_url)).to have_been_made.once
-    end
   end
 end
diff --git a/spec/services/remove_status_service_spec.rb b/spec/services/remove_status_service_spec.rb
index 482068d58..2b789ed84 100644
--- a/spec/services/remove_status_service_spec.rb
+++ b/spec/services/remove_status_service_spec.rb
@@ -108,4 +108,22 @@ RSpec.describe RemoveStatusService, type: :service do
       )).to have_been_made.once
     end
   end
+
+  context 'when removed status is a reblog of a non-follower' do
+    let!(:original_status) { Fabricate(:status, account: bill, text: 'Hello ThisIsASecret', visibility: :public) }
+    let!(:status) { ReblogService.new.call(alice, original_status) }
+
+    it 'sends Undo activity to followers' do
+      subject.call(status)
+      expect(a_request(:post, bill.inbox_url).with(
+               body: hash_including({
+                 'type' => 'Undo',
+                 'object' => hash_including({
+                   'type' => 'Announce',
+                   'object' => ActivityPub::TagManager.instance.uri_for(original_status),
+                 }),
+               })
+             )).to have_been_made.once
+    end
+  end
 end