A few days ago I upgraded my wiki to 1.8.1 (from 1.7.something), and
all of my parser function hooks (the tags with {{#Blah: ...}} syntax
added with $wgParser->setFunctionHook) stopped working. (That is,
they started showing up verbatim, unparsed.) I upgraded the
ParserFunctions extension, the one with the conditional evaluation
things and such, to the latest version, and they now work fine. But
my own custom-written hooks still don't work. I tried comparing the
new version of ParserFunctions to the one I previously had installed,
but I couldn't figure out what changes were necessary to make it work
in the new version. What changed about the semantics of adding such
hooks in MW 1.8?