diff --git a/app/serializers/rest/instance_serializer.rb b/app/serializers/rest/instance_serializer.rb
index 084701657e..cced83587d 100644
--- a/app/serializers/rest/instance_serializer.rb
+++ b/app/serializers/rest/instance_serializer.rb
@@ -77,7 +77,7 @@ class REST::InstanceSerializer < ActiveModel::Serializer
       },
 
       media_attachments: {
-        supported_mime_types: MediaAttachment::IMAGE_MIME_TYPES + MediaAttachment::VIDEO_MIME_TYPES + MediaAttachment::AUDIO_MIME_TYPES,
+        supported_mime_types: MediaAttachment.supported_mime_types,
         image_size_limit: MediaAttachment::IMAGE_LIMIT,
         image_matrix_limit: Attachmentable::MAX_MATRIX_LIMIT,
         video_size_limit: MediaAttachment::VIDEO_LIMIT,
diff --git a/app/serializers/rest/v1/instance_serializer.rb b/app/serializers/rest/v1/instance_serializer.rb
index 636925b973..7f9f21c5af 100644
--- a/app/serializers/rest/v1/instance_serializer.rb
+++ b/app/serializers/rest/v1/instance_serializer.rb
@@ -69,7 +69,7 @@ class REST::V1::InstanceSerializer < ActiveModel::Serializer
       },
 
       media_attachments: {
-        supported_mime_types: MediaAttachment::IMAGE_MIME_TYPES + MediaAttachment::VIDEO_MIME_TYPES + MediaAttachment::AUDIO_MIME_TYPES,
+        supported_mime_types: MediaAttachment.supported_mime_types,
         image_size_limit: MediaAttachment::IMAGE_LIMIT,
         image_matrix_limit: Attachmentable::MAX_MATRIX_LIMIT,
         video_size_limit: MediaAttachment::VIDEO_LIMIT,