I've got a live web server running 12.04 which is in desperate need of an update. I cannot upgrade to 16.04 as the new version of PHP is not compatible with the hosted site as well as a few other packages that won't be compatible.
Is there a way I can run do-release-upgrade for the 14.04 release?
You can check the release you'll get with do-release-upgrade by adding the -c flag like so:
do-release-upgrade -c
As far I understand, there is not yet an upgrade possibility for upgrading 12.04 LTS to 16.04 without going step by step (i.e. to 14.04 on the first run), so do-release-upgrade can be expected to do exactly what you want.
I tested this just now.
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 12.04.5 LTS
Release: 12.04 Codename: precise
Then:
$ sudo do-release-upgrade
Checking for a new Ubuntu release
Get:1 Upgrade tool signature [198 B]
et:2 Upgrade tool [1,156 kB]
Fetched 1,156 kB in 0s (0 B/s)
authenticate 'trusty.tar.gz' against 'trusty.tar.gz.gpg' extracting 'trusty.tar.gz'
You cannot currently upgrade directly from 12.04 to 16.04; you have to upgrade to 14.04 in-between. So simply running the following will upgrade you to 14.04:
sudo do-release-upgrade
Then if you don't want to upgrade again to 16.04, just stop there rather than performing another upgrade.
Or (for the GUI way - the relevant program is also known as the Software Updater and can be searched and found in the GUI under that name):
update-manager
For this though once you are completely up-to-date with all the latest updates it will show you an Upgrade... button which will allow you to upgrade to 14.04.
