Chad [innocentkiller@gmail.com] writes:
The real failure is because preferences were rewritten entirely in 1.16.x and I don't believe back-compat was maintained for the old hooks. Take a look at the GetPreferences hook[0] for more info.
Thanks Chad. I'll check it out.
The UserToggles hook is still in the code though, and documented on mediawiki.org; hopefully that will get fixed if it's really deprecated.
DanB