Thank You for taking Your time. I've done 'sudo apt update' then 'sudo apt upgrade'. no help unfortunatelly.
Here's the requested output: $ sudo apt policy libudev-dev libudev-dev: Installed: (none) Candidate: 245.4-4ubuntu3 Version table: 245.4-4ubuntu3 500 500 http://pl.archive.ubuntu.com/ubuntu focal/main amd64 Packages -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1792980 Title: cannot install libudev-dev To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/net-snmp/+bug/1792980/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs