This cut-off is in place because the improvements to user-roles in WordPress 4.7 are really that important, and all future bug-fix releases to 2.5 and major releases going forward will be taking advantage of them.
If you’ve updated to 4.7 and are one of the unlucky few to get stung by the missing-menu bug, please accept my sincere apologies along with an update to 2.5.12 to relieve the itching.
bbPress 2.5.11 is out, and is a maintenance release for all previous 2.x versions. 2.5.11 includes support for the soon to be released WordPress 4.7. If you’re planning on updating to WordPress 4.7 right away, you’ll want to update to bbPress 2.5.11 immediately.