Linux Mint 20.2 "Uma" beta ISOs are undergo testing and are due soon. As with the other versions in the Linux Mint 20.x series, this update will be supported until April/May of 2025. Once security updates stop, you won’t be safe - especially if you connect to the Internet with the device.
Cinnamon 5.0 has been released with many improvements that make the desktop environment more secure, stable and reliable, including new GUI and CLI tools for checking, listing, and performing updates of Cinnamon Spices.
Linux Mint 20.2 'Uma' is set for a beta release by mid-June, with a selection of useful new features and improvements. Just like the rest of the 20.x series, 20.2 will be supported until around April or May of 2025. At this point, users will need to upgrade if they want their system to remain secure.
