Because 2.5.5 was so good 2 weeks ago, we are releasing bbPress 2.5.6 tonight. It fixes 1 issue with subscription notification emails that was plaguing a few of our more sophisticated installations.
If you’re using any version of bbPress 2.x and have been hesitating to upgrade, please consider doing so today. If you need help, please reach out in our support forums and someone will help you get updated.
Thanks to netweb, DJPaul, and mordauk for their diligence in patching and prioritizing this issue.