Saurik has released an update to Cydia Installer that fixes a SpringBoard lock up issue with iOS 8.3.
A “proactive” fix for iOS 8.3 added in Cydia 1.1.17 caused SpringBoard to lock up if users killed Cydia using the iOS task switcher. This fix is designed to fix an issue that should be present on iOS 8.3, but TaiG’s jailbreak seems to provide a workaround in the form of a kernel patch. This will be investigated for later releases, but in the mean time the fix has been removed.
You can install the update from the Changes tab in Cydia. TaiG has released an updated jailbreak that fixes issues with Cydia Substrate.