This notice is being sent to wikitech-l for the benefit of technical subscribers who aren't subscribed to that list, due to concern that these changes may affect many API clients. For notification of all breaking changes to the Action API, please subscribe at https://lists.wikimedia.org/mailman/listinfo/mediawiki-api-announce.

Error codes for parameter validation errors are changing. Among others, "noX" becomes "missingparam" and "unknown_X" becomes "badvalue". See the full announcement at https://lists.wikimedia.org/pipermail/mediawiki-api-announce/2020-February/0... for details.

Various unusual values for integer-type parameters will no longer be accepted, basically anything that isn't an optional ASCII sign ('+' or '-') followed by ASCII digits. See https://lists.wikimedia.org/pipermail/mediawiki-api-announce/2020-February/0... for details.

Both of these changes will most likely go out to Wikimedia wikis with 1.35.0-wmf.19. See https://www.mediawiki.org/wiki/MediaWiki_1.35/Roadmap for a schedule.