As of July 17, 2020 Ubuntu MATE 19.10 will reach 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.
Or via the Terminal:
Still using 19.10?
The upgrade path will be to the current LTS release, 20.04 , supported until April 2023 . To upgrade, open Software Updater and follow the steps.
Or alternately, via the Terminal: