The inbox polling system (used for processing queued messages when the session becomes available) has been refactored to accept an explicit enabled parameter. This improves control flow by allowing the polling behavior to be conditionally disabled rather than relying on implicit checks throughout the function.
Evidence
Inbox poller function signature change — ijq() at line ~547956 (search for "[InboxPoller]")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.