µg UnifiedNIp cannot be upgraded, yet I get notifications for it

I'm using F-Droid 0.99.2 and since upgrading to that version, I keep getting daily upgrade notifications for a package called "µg UnifiedNIp (no GAPPS)". I haven't installed this and I don't know what it is. But when I try to apply the upgrade, I get the message: "The new version is signed with a different key to the old one. To install the new version, the old one must be uninstalled first." If I then try to uninstall the package, I get an error: "Failed to uninstall due to an unknown error". So I have a package F-Droid wants me to upgrade, but won't let me, and I can't get rid of it either.