If you are using a GNOME-based UI, running apk upgrade -a might be broken since a few weeks ago with the following error:
$ sudo apk upgrade -a
ERROR: unable to select packages:
power-profiles-daemon-0.30-r1:
breaks: tuned-ppd-2.26.0-r1[!power-profiles-daemon]
satisfies: postmarketos-base-ui-gnome-9-r0[power-profiles-provider]
This is due to a bug in apk-tools that was fixed in version 3.0.0_rc9. To get out of this and resume normal behaviour you can upgrade the apk-tools package selectively like so:
$ sudo apk upgrade apk-tools
See #4117 and apk-tools#11170 for more details.