Thread:Extension talk:MassMessage/Incompatible with existing recipient list format/reply (6)

Parser functions generally use (or ) while MediaWiki page templates generally use. It's a subtle distinction, but it was unavoidable breaking change given outside constraints. Interwiki syntax would've been nice to use, but it presents a lot of headaches when trying to pull the data out.

As Lego notes, a simple find and replace should be fine for local lists. An edit or two to m:Template:Target will likely suffice for global message delivery. Fortunately only two wikis will need any help and I hope anyone who gets stuck will know to ask for help at m:Talk:MassMessage.