failed Ubuntu upgrade from 18 to 20

[bnovecosky]

Opened Software Updater which notified me that I'm on 18.04LTS and 20.04.1 LTS is available. I clicked upgrade and then it fails.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubuntu-release-upgrader-core 1:18.04.38
ProcVersionSignature: Ubuntu 5.4.0-52.57~18.04.1-generic 5.4.65
Uname: Linux 5.4.0-52-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.17
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: ubuntu:GNOME
Date: Thu Oct 22 16:50:43 2020
InstallationDate: Installed on 2019-06-12 (498 days ago)
InstallationMedia: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to bionic on 2020-10-22 (0 days ago)
VarLogDistupgradeTermlog:

[Daniel Letzeisen (dtl131)]

You have oibaf PPA still enabled. Please follow the directions and run ppa-purge on it (and other PPA's you may have enabled) to restore stock 18.04 packages. Then, try to upgrade again.

[Launchpad Janitor (janitor)]

[Expired for ubuntu-release-upgrader (Ubuntu) because there has been no activity for 60 days.]