Changing preinstalled apps

I want to use acalendar+ to handle my caldav-tasks (yes, it is no FOSS app). For this I need Opentasks. In my build however, foundation.e.tasks is preinstalled. Tasks in that app are not detected by acalendar+. I wanted to install Opentasks but this is not possible together with e.tasks. Uninstalling e.tasks and installing opentasks fails with this error message: “Failure [INSTALL_FAILED_DUPLICATE_PERMISSION: Package org.dmfs.tasks attempting to redeclare permission org.dmfs.permission.WRITE_TASKS already owned by foundation.e.tasks]”

Has anyone an idea how to access my tasks with acalendar?

/e/tasks is a system app. How did you try to uninstall e.tasks?

Are you sure that this purchase-app will work with microG?

I uninstalled using the commands adb shell and pm uninstall -k --user 0 foundation.e.tasks.

At least for the calendar it works…

uninstall -k --user 0 uninstalls the app for the current user only. Tasks.apk also cooperates with org.dmfs.tasks (base.apk).

I would try to use the file manager of TWRP to disable the files only by renaming them.

Before they go any further: Are you sure that this purchase-app will work with microG?

At least for the calendar it works and is running. I don’t know about the tasks section. That’s what I want to try. It also dos not find google tasks but that I thought is because of microG and completely OK for me.