Thanks for sharing the results.
FYI in the future, I believe you can just connect your device to your computer and use iTunes to "transfer purchases". This will put a copy of the currently installed xfinity app IPA file onto your computer. This file allows you to install that version whenever you want. If xCon does not work with the new update, just delete the app from your device and use this IPA file to install the version which was working with xCon.
This way you won't ever have to worry about installing a bad update. I transfer purchases all the time and keep old copies of apps to have this safety net.
Installing IPA files is really easy. You can use the app called IPA Installer from the BigBoss repo in Cydia, iFunBox (this is what I use), or iTunes (I think...been a while since I've used iTunes for anything other than transfer purchases haha). There are probably a bunch of other ways to install IPA files too. Bottom line is, its super easy to create this fallback option and also allows you to never have to ask around if some new version of an app works.
There are some caveats but for the most part this should work. You can run into issues if an app is pulled from the App Store. Sometimes the IPA file won't install correctly. But of course if you're only concerned about apps which rely on xCon, then I don't see those types of apps getting pulled anytime soon haha. Hope this helps.