Cydia Substrate is the most important package of Cydia, most tweaks released by tweak and app developers for iDevices with jailbreak using it to provide us with various functions not normally available in the operating system. During these days this plugin was updated by the Cydia creator, versions 0.9.5100 and 0.9.5101 being released for terminal owners who have iOS 8.1 jailbreak, the first of which implements the possibility of running multiple daemons, the second of which solves performance problems of the first of them.
Cydia Substrate 0.9.5101 fixes an incompatibility introduced in 0.9.5100 with some combinations of extensions (the most common conflict was having both CC Settings and GroovyLock). Cydia Substrate 0.9.5100 includes features requested by developers, so their extensions may require this update: it can inject into more iOS 8 daemons, find more private symbols, move more arm64 instructions, and hook even shorter armv7 functions.
Since one of the updates implements new options for developing tweaks, there is a possibility that future packages will require this update, so it's better to do it now to avoid hassles in the future. Cydia Substrate is available for free download in Cydia.
