A new update was just pushed by Pangu Team for the iOS 8 Pangu jailbreak. Here is a short tutorial on how to apply it right now from your device.
This update brings fixes for iMessage, Safari and Cydia Substrate loading. The actual version can`t be downloaded right now (Pangu app is still at version 1.0.1), but here are the steps required to update Pangu if you already jailbroken your device.
Note: You don`t need to have a passcode set, because this might cause a boot loop.