The CirrusSearch API provides a "morelike:" prefix that is specifically intended for retrieving similar articles. This would be an improvement over our current method of getting similar articles (a simple full-text search query).
- Add a feature flag to split users 50/50 for using the old method vs. the new.
The event logging schema (https://meta.wikimedia.org/wiki/Schema:MobileWikiAppArticleSuggestions) has been modified to include a "readMoreSource" parameter used for logging whether the old or new method was used (0=old, 1=new). Note that the "version" parameter was removed from the schema.