The current implementation of the search update pipeline does support an early version of the page-change schema (/development/mediawiki/page/change/1.0.0).
This was removed and updated to a stable version /mediawiki/page/change/1.0.0.
AC:
- the pipeline is able read events from the page-state MW stream using the /mediawiki/page/change/1.0.0 schema.