Hello, I also have the same issue. Creating or pushing updates to AppClips was working fine last month, but now I see the same error. { "errors" : [ { "id" : "38a14d58-ff3a-4c77-8e0d-dba260685700", "status" : "409", "code" : "ENTITY_ERROR.INCLUDED.INVALID_ID", "title" : "The provided entity id is invalid", "detail" : "The provided included entity id 'EN' has invalid format", "source" : { "pointer" : "/included/0/id" } } ] } It looks like @pumpkinpaul and I have done some of the same investigation and testing. I agree with everything he has outlined and we have come to the same frustrating conclusion. A bug was probably introduced sometime in between these two dates. I have this information from recorded HTTP interactions as part of our automated testing. I have included the request IDs here in case they help with the debugging. Success on Nov 12 with a Daiquiri version of 25RELEASE142: X-Request-Id: - TQFDTUQATMJM246YITQXKVXIPM Failure on Dec 19 with a Daiquiri version of 25HOTFIX33: X-Request-Id: - XVPVR2MEFH7DBE5IEV5YZ6R5JI Please find the failed request attached. The same payload was sent last month with only a slight tweak to the URL so as not to get a conflict during creation.