After upgrading to gaim-1.1.0, a warning is displayed saying that gaim-encryption was compiled with an older version of gaim and may not work. There should either be a warning at the end of the gaim ebuild saying you can re-emerge gaim-encryption to get rid of this message, or, a re-emerge of gaim-encryption should be forced.
Uhh ... there already IS a message and has been in the gaim ebuild for a long long time. ewarn "If you are merging ${P} from an earlier version, you will need" ewarn "to re-merge any plugins like gaim-encryption or gaim-snpp."