The Mint project today unlocked the upgrade path from Linux Mint 20 "Ulyana" to the latest version Linux Mint 20.1 “Ulyssa.”
The distribution is based on Ubuntu 20.04.1 LTS (Focal Fossa) and runs on the Linux kernel 5.4 LTS. Linux Mint 20.1 "Ulyssa" was officially released on January 8, 2021, with an upgraded desktop environment (Cinnamon 4.8), support for Web Apps, a new IPTV player, print and scan enhancements, and more.
Because Linux Mint 20.1 uses the same package base as Linux Mint 20, you do not need to download the new ISOs to upgrade your existing installations.
You just need to upgrade, which is an easy process for anyone using Linux Mint.
First of all, make sure you have a backup of your files in case something goes wrong. Second, you need to turn off the screensaver, and download the latest updates using the Update Manager.
You are now ready to upgrade your Linux Mint 20 installation to Linux Mint 20.1.
You need to activate the System Upgrade utility and then from the Edit menu click on Upgrade to "Linux Mint 20.1 Ulyssa".
The upgrade screen will appear and you will need to follow the instructions to proceed with the process, which will take from a few minutes to an hour or more, depending on the speed of your connection and the specifications of your computer. 
If you are prompted to override any configuration files during the upgrade process, do so.
When the upgrade is complete, simply restart your computer to enjoy Linux Mint 20.1 "Ulyssa" and its new features.
Alternatively you can use usrmerge.
Information about usrmerge can be found here https://www.freedesktop.org/wiki/Software/systemd/TheCaseForTheUsrMerge/.
Open a terminal and run the command:
apt install usrmerge
Then restart your computer.
