Saurik recently pushed a small Cydia Substrate update to fix issues with devices running versions of iOS prior to iOS 5. The update, which comes in at version 0.9.6011, was pushed to fix a problem that arose during the 0.9.6xxx series of Cydia Substrate updates.
While this update is small, and probably only affects a handful of jailbreakers, the more important issue of jailbreak stability was mentioned by Saurik recently via Twitter. As you're likely aware of, some have been experiencing issues with non-recoverable boot loops after restarting their jailbroken devices running iOS 9...