Unable to update 18.04 to 18.10

[Ankit]

$ sudo apt do-release-upgrade
.
.
.

Checking package manager
Reading package lists... Done
Building dependency tree
Reading state information... Done

Calculating the changes

Calculating the changes

Could not calculate the upgrade

An unresolvable problem occurred while calculating the upgrade.

This can be caused by:
* Upgrading to a pre-release version of Ubuntu
* Running the current pre-release version of Ubuntu
* Unofficial software packages not provided by Ubuntu

If none of this applies, then please report this bug using the
command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal.

Restoring original system state

Aborting
Reading package lists... Done
Building dependency tree
Reading state information... Done

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubuntu-release-upgrader-core 1:18.04.29
ProcVersionSignature: Ubuntu 4.13.0-22.25-generic 4.13.13
Uname: Linux 4.13.0-22-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: ubuntu:GNOME
Date: Thu Dec 6 21:08:11 2018
InstallationDate: Installed on 2016-10-24 (773 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to bionic on 2018-12-07 (0 days ago)
mtime.conffile..etc.update-manager.release-upgrades: 2018-12-06T10:28:19.136187

[Juhani Numminen (jsonic)]

Hi!

It seems like you've installed 3rd party drivers. Please remove them and see if the upgrade succeeds then.

Quoting https://launchpad.net/~oibaf/+archive/ubuntu/graphics-drivers

=== Upgrading to a newer Ubuntu ===
It is *strongly* suggested to remove all packages from this PPA before updating to a newer Ubuntu release. See the section "Revert to original drivers" later on.
Then, after the upgrade, you can add again this PPA.

=== Revert to original drivers ===
To revert to standard Ubuntu drivers type the following in a prompt shell:
$ sudo apt-get install ppa-purge
$ sudo ppa-purge ppa:oibaf/graphics-drivers

[Launchpad Janitor (janitor)]

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