Upgrade Jenkins on Ubuntu12.04

I just installed Jenkins on my Ubuntu 12.04 server using 'apt-get install jenkins' command.
But it's too old.
How to upgrade it?

Remove your existing jenkins first.
apt-get autoremove jenkins

Follow the steps from official site:


This is the Debian package repository of Jenkins to automate installation and upgrade. To use this repository, first add the key to your system:

wget -q -O - http://pkg.jenkins-ci.org/debian/jenkins-ci.org.key | sudo apt-key add -
Then add the following entry in your /etc/apt/sources.list:
deb http://pkg.jenkins-ci.org/debian binary/
Update your local package index, then finally install Jenkins:

Run two commands below:
apt-get update
apt-get install jenkins

Very easy!