I came here to get Ubuntu MATE for Raspberry Pi, and was disappointed to see that support is still stuck at a beta version of v18.04.2. Ubuntu v18.04.2 was released almost a year and a half ago.
Also, when you click-thru to download v18.04.4 for RPi, you are instead served v18.04.2-beta1, but thanked for downloading v18.04.04!
It is obvious that RPi support is an afterthought, and isn't really happening. I suggest the distro drop all pretenses of RPi support, and drop it. Unfortunately, it doesn't appear that this free up any people to put more effort into UM's general development effort as it doesn't appear anyone has been devoting ANY time to the RPi.