Default [Q] How to update Calendar app?

Hi,
I just switched to Null 22.1 and I run into the problem where the buillt in calendar (into Fomey's ROM) is kinda old - therefore it doesn't show all the colors for my events. How do I uninstall it? I tried to remove the APK from system/app with x-plore after giving root rights, but it always end up in a restart. Please help.

EDIT:
Problem solved. Did the update through Play Store, now colors are OK. Fomey, maybe you can consider including updated Calendar in next version?