Whether your environment is Microsoft Azure, Digital Ocean or Amazon AWS, there is a universal command baked into every distribution of Ubuntu Server which will upgrade to the next release. It is reliant on the Canonical Ubuntu repo's and not whatever provider environment you're on.
I had an issue while trying to upgrade from Ubuntu Server 14.04 LTS to 16.04 LTS running in AWS and found out that Ubuntu Server LTS won't upgrade to to the next major release unless that build version is ≥ .1. So for example it won't consider 16.04 until 16.04.1 is released. But luckily there is a way to force the upgrade which is what I did for the front end Nginx proxy for this website.
It is also possible to use do-release-upgrade to upgrade to a development version of Ubuntu. To accomplish this use the -d switch:
For further stability of a LTS release there is a slight change in behaviour if you are currently running a LTS version. LTS systems are only automatically considered for an upgrade to the next LTS via
do-release-upgrade with the first point release. So for example 14.04 will only upgrade once 16.04.1 is released. If you want to update before, e.g. on a subset of machines to evaluate the LTS upgrade for your setup the same argument as an upgrade to a dev release has to be used via the
$ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 16.04 LTS Release: 16.04 Codename: xenial