While I tried (and did) keep b/c for quite some time, I realized that this became harder over time and at some point it broke. After a discussion with Chris we need to reevalute this and decide whether we want to restore b/c or maintain branches for older MW versions.

CCing Markus as he might have an opinion on this (from a 3rd party point of view).

This is a policy question for release engineering - so far I expected compatibility only for the current corresponding branch.

(In reply to Andre Klapper from comment #2)

This is a policy question for release engineering - so far I expected
compatibility only for the current corresponding branch.

This currently depends on the specific extension. Some (especially ones actively being developed) break compatibility almost immediately, while some (for example several maintained by WMF's Language team) stay compatible with at least one or two MW versions back. (This is, sadly, usually not documented anywhere.)

The extension has a REL1_19 branch (that should probably have a lot of updates applied to it). So we can keep parallel branches. Those are (supposed to be) what is distributed with the tarball.

We tried to keep AbuseFilter b/c for as long as possible. And if there are good ways to keep master working with 1.19, then we should make an effort to do that. But if we start limiting features, or the logic is less understandable because we're trying to support old versions, we should just rely on the branch to keep working with the old version of mediawiki.

Security issue should always be backported to the branches. I'm pretty sure we've done that.

so current viewpoint is wontfix/decline this bug? Anyway MW 1.19 (LTS) is only official supported until May 2015.