As of July 20, 2023 Ubuntu MATE 22.10 has reached EOL (End of Life) and is no longer supported. There will be no more updates or security patches for this release.
Being an interim release, these are only supported for 9 months.
How do I check?
See which version you are running by opening the System Monitor and checking the System tab.
Still using 22.10?
The upgrade path will be to the current interim release, 23.04, supported until January 2024. To upgrade, open Software Updater and follow the steps.
When you download a version to install it tells you if it's LTS or Interim and in fact on the download page it even tells you when it's supported through. Suggesting someone gave you an impression or anything else was most likely a misunderstanding on your part. You can go right now to the download page and see that 22.10 is an Interim release and has support through July 2023, 23.04 is an Interim release and has support through Jan 2024 and the only release that has long term support (LTS) is 22.04, and it's supported through Apr 2025.
No Ubuntu MATE release has ever had 5 years of support as long as I've been using it (4 years now). But I don't even question it because it tells you on the very link that you click to download it.
Now, a bit of advice from a person who's used LTS and Interim releases. I don't really know what the differences are even though it says what they are if you read about Ubuntu MATE LTS releases. I have the flexibility to delete the programs I want and install the programs I want and that's the main thing I'm concerned about, so frankly LTS is probably best for most people so you have a long time before having to update your OS. I've heard people say you're frozen into certain software, but I haven't had issues deleting or installing anything and updating software as needed. Maybe for a small package of software you get frozen into a certain version and can only install updates to that version but I'm guessing for most people who are used to using Windows it's not an issue at all. I'm used to installing an Office set of applications for instance and using it for many years because I'd rather use the same thing because I get used to its behavior and I learn how to do what I want quickly. I don't want to keep relearning a software package every couple of years.
That's my two cents. I installed 22.04 and am glad I did though I do have issues for which I don't know if it's the Ubuntu core or MATE, I think it's the core, but I have a dual boot system and drives that are EXT4 and drives that are NTFS where I can use data in either OS so it's not the most friendly system for Ubuntu to deal with. Most my issues arise from using a file explorer of all things, but I also have Caja AND Thunar installed so maybe I shouldn't be surprised. I had the same issues with an older system and older MATE, basically a similar config though, dual boot, dual file explorers in MATE and a mix of NTFS and EXT4 drives.
Note: The LTS versions have 5 years of Ubuntu support, security and patches and the MATE overlay is 3 years, but by then they have most features ironed out and are working on next LTS which will have the same 5 yr. 3 yr. support.
So MATE will continue for 23.04... etc. Good. I do, however, have issues with things like Caja and the like. I used to stick to Gnome2, I like compiz and gnome-panel, etc. But it was becoming more and more flakey like gnome-panel dying and the like. Then somebody said to switch to MATE and I did. Things were a lot better for me. But now some more gremlins seem to be coming up. And with the EOL announcements and I believe I got an email that sounded like MATE was going away so I figured these remaining quirks would not be fixed so I wouldn't report them. Now if MATE is continuing I will become more active in reporting problems.
There is nothing that suggests Ubuntu MATE is going anywhere. The typical pattern is that an LTS version (distro) comes out every 2 years, so the next LTS should be 24.04. There are two releases a year. In a year with the LTS launching there is one Interim and one LTS, and in the year with no LTS launch there are two Interim launches.
My only concern is they change the DE to the point it no longer works like 22.04, where the default is a bar on top and bottom which is the EXACT reason I use Ubuntu MATE. It works very well for my needs. With 23.04 they shifted for a default behavior of a single bar, but you can still select the past behavior by going to themes and changing it back. My understanding is this is the original Gnome 2 DE design. If this project ever makes it to where you can't select bar on top/bar on bottom with the BEHAVIOR of those bars acting like it currently does, then there's no reason for me to keep using Ubuntu MATE. Ubuntu has multiple DEs and longer support, so I'd just switch over to Ubuntu or maybe revisit the different distros after I lose support for the DE I like. As long as 24.04 works like 22.04 or has the ability to work like that without spending hours configuring how the bars work, I'll install 24.04 as a preemptive measure to ensure I have 3 years of support with the DE I like.
5 years of Ubuntu support as was mentioned is only for the core. If you have issues related to using software and it has a problem with MATE, that's what won't get supported for more than 3 years, Also, even though the core has 5 years of support (based on the year of release not when YOU downloaded it), that doesn't mean you'll get updates, because the update management is via the MATE project. You can probably manually update the core along with manually updating any other software. I don't think you'll get any notices though. Maybe I'm wrong? Better to just upgrade to a new version.
System Monitor and checking the System tab.
Software Updater and follow the steps.
Terminal: