My Linode mentioned that a new Ubuntu release is available. Is my Ubuntu Linode out of date? How does Ubuntu's update cycle work?

Hey there,

There are a lot of important parts to this question, so lets break down a few things:

Ubuntu is the GNU/Linux distribution that you are running, and it is provided by the company Canonical. Canonical names its Ubuntu releases after the year and month that the distribution is released. For example, 14.10 was released in October 2014, while the release it mentioned above (15.04) was released April 2015. The first two digits are the year it was released, while the last two digits are the month that it was released.

Canonical releases its distros under two tracks, LTS, or Long Term Support, where support is provided for around 5 years, and its standard release track which is supported generally for nine months. LTS releases occur in April on every even year, so for example, the following releases would be LTS (14.04,16.04,18.04, with April of this year sporting 20.04) while any odd year or release in October is under the standard track (such as 14.10 and 15.04). You may also see additional numbers after this naming convention, such as 18.04.3. This is just a continued upgrade for the LTS release cycle. You can see what distros are currently supported via this link here.

When a distro has reached the end of its support track, it enters an End of Life, or EoL phase. When you hit EoL, it generally means that Canonical will not support that release with any future updates. This means that both 14.10 and 15.04 are currently in their End of Life phase.

Now that everything is been explained a bit, lets talk about what this may mean to you. First off, no further support means that if a security flaw is discovered in one of the packages (such as java, apache, etc) that your Linode uses, and a fix will not be passed along to old updates, you are likely vulnerable to it. It is important to note that any Kernel level related flaws may not effect you, if you are using Linodes provided kernel, and it is up to date.

If it is important to you that these services remain secure, you might want to consider upgrading the distro to make sure that you are secure.

Note, running updates is very likely to break your install, as Ubuntu has changed pretty dramatically over the years. It is highly recommended to create a new fresh install, then migrate your data over manually, as this will lessen the chance of services not working as the switch over happens.

If it is not important that the services remain secure: don't do anything, assuming all is working :)