Following a Cydia Substrate update on Wednesday that improved hooking and added preliminary support for iOS 14, the package received a second update early Thursday morning, this time bringing it up to version 0.9.7103.
Cydia Substrate is used for tweak injection on both the checkra1n and unc0ver jailbreaks, albeit only up to A11 devices for the latter as Cydia Substrate doesn’t support A12 or newer handsets. If you’re using a supported platform, then this update is available from Sam Bingner’s default repository and should appear after refreshing your sources.