User blog comment:Rappy 4187/Technical Update: April 15, 2015/@comment-1251315-20150416123403/@comment-957747-20150427205233

@452 - not incompatible per se. The CSS was changed last week but the social buttons were delayed which caused the issue. Tomorrow, the CSS will be re-added (since we reverted the issue) with the rollout of the social buttons.