diff --git a/app/helpers/jsonld_helper.rb b/app/helpers/jsonld_helper.rb
index 09446c8be2..d82a073320 100644
--- a/app/helpers/jsonld_helper.rb
+++ b/app/helpers/jsonld_helper.rb
@@ -10,7 +10,7 @@ module JsonLdHelper
   end
 
   def value_or_id(value)
-    value.is_a?(String) ? value : value['id']
+    value.is_a?(String) || value.nil? ? value : value['id']
   end
 
   def supported_context?(json)
diff --git a/app/lib/activitypub/activity/create.rb b/app/lib/activitypub/activity/create.rb
index 5c59c4b249..114aed84f9 100644
--- a/app/lib/activitypub/activity/create.rb
+++ b/app/lib/activitypub/activity/create.rb
@@ -91,7 +91,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
 
   def resolve_thread(status)
     return unless status.reply? && status.thread.nil?
-    ThreadResolveWorker.perform_async(status.id, @object['inReplyTo'])
+    ThreadResolveWorker.perform_async(status.id, in_reply_to_uri)
   end
 
   def conversation_from_uri(uri)
@@ -118,8 +118,19 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
   end
 
   def replied_to_status
-    return if @object['inReplyTo'].blank?
-    @replied_to_status ||= status_from_uri(@object['inReplyTo'])
+    return @replied_to_status if defined?(@replied_to_status)
+
+    if in_reply_to_uri.blank?
+      @replied_to_status = nil
+    else
+      @replied_to_status   = status_from_uri(in_reply_to_uri)
+      @replied_to_status ||= status_from_uri(@object['_:inReplyToAtomUri']) if @object['_:inReplyToAtomUri'].present?
+      @replied_to_status
+    end
+  end
+
+  def in_reply_to_uri
+    value_or_id(@object['inReplyTo'])
   end
 
   def text_from_content
diff --git a/app/serializers/activitypub/activity_serializer.rb b/app/serializers/activitypub/activity_serializer.rb
index d20ee99206..349495e84e 100644
--- a/app/serializers/activitypub/activity_serializer.rb
+++ b/app/serializers/activitypub/activity_serializer.rb
@@ -10,7 +10,7 @@ class ActivityPub::ActivitySerializer < ActiveModel::Serializer
   end
 
   def type
-    object.reblog? ? 'Announce' : 'Create'
+    announce? ? 'Announce' : 'Create'
   end
 
   def actor
@@ -24,4 +24,8 @@ class ActivityPub::ActivitySerializer < ActiveModel::Serializer
   def cc
     ActivityPub::TagManager.instance.cc(object)
   end
+
+  def announce?
+    object.reblog?
+  end
 end
diff --git a/app/serializers/activitypub/note_serializer.rb b/app/serializers/activitypub/note_serializer.rb
index 4061b9ce45..15031dfdc4 100644
--- a/app/serializers/activitypub/note_serializer.rb
+++ b/app/serializers/activitypub/note_serializer.rb
@@ -9,6 +9,7 @@ class ActivityPub::NoteSerializer < ActiveModel::Serializer
   has_many :virtual_tags, key: :tag
 
   attribute :atom_uri, key: '_:atomUri', if: :local?
+  attribute :in_reply_to_atom_uri, key: '_:inReplyToAtomUri'
 
   def id
     ActivityPub::TagManager.instance.uri_for(object)
@@ -64,6 +65,12 @@ class ActivityPub::NoteSerializer < ActiveModel::Serializer
     ::TagManager.instance.uri_for(object)
   end
 
+  def in_reply_to_atom_uri
+    return unless object.reply?
+
+    ::TagManager.instance.uri_for(object.thread)
+  end
+
   def local?
     object.account.local?
   end