To be slightly more helpful, it seems that some banking apps now work on Jolla’s newly signed Android image and some don’t. On the previous unsigned image the vast majority did not work at all. For me, in the UK, on 4.4.0.64 X10 III, the Lloyds business banking app works fine, but the Santander one does not. In general banks are tightening the security for their apps so they are becoming less tolerant of rooted phones, AOSP Android, etc. You may find you can still use mobile banking via the web browser with your bank. I can do this with Santander, although it always serves up the desktop site rather than the mobile site which is a bit of a pain.