Jailbroken users will hardly see Cydia Substrate getting updated unless a new jailbreak utility come out. Saurik tends to update it so that developers can release a new version to their jailbreak tweaks that support the new jailbroken firmware. Today was one of the many exceptions, due to bugs report and such, Cydia Substrate has been updated to version 0.9.6110.
Specifically, the update brings fixes for corrupt extensions, often used by the developer for obfuscation purposes. In previous versions, Saurik made an attempt to have Cydia detects whether the upcoming tweaks will cause crashing or not, as a result, Cydia Substrate ending crashing itself.