When running the core update for x86 from release 126 to 131 on a PC Engines APU, pakfire is stuck on release 127.
Tried
# echo 126 > /opt/pakfire/db/core/mine
# pakfire upgrade
But got
PAKFIRE UPGR: core-upgrade-127: Decrypting…
tar: /lib/libc.so.6: version `GLIBC_2.28’ not found (required by tar)
How can I recover without reinstall?
Hi,
When running the core update for x86 from release 126 to 131 on a PC Engines APU, pakfire is stuck on release 127.
first, I cannot resist strongly recommending you to re-think your approach to security: Core Update 126 has been released about 1,5 years ago, so your IPFire machine was/is vulnerable to the entire bunch of security issues being fixed within the last 1,5 years.
Sorry, but in my humble opinion, this most probably is not the security level you aimed at if you run a firewall. 
How can I recover without reinstall?
As far as I can recall, there was a breaking change around that timespan. Some older system have too small /boot partitions as well, which is why newer releases’ kernel do not fit into. Re-installing your system is probably the most straightforward and less troublesome way to go.
Thanks, and best regards,
Peter Müller