The reason is that Xrumer has upped a new version and Xenforo spam is one of its major updates. It has only been released in Russian version in the last few hours and the english version is expected to go live very soon. Expect to get HIT big time guys!
For now only Russian version of Xrumer is updated. The update on the Xrumer english version is going to be released in a week. Botmaster has specially mentioned XenForo spamming capabilities of the updated Xrumer. This software can churn out 1000 posts per minute. Expect to get nailed like crazy