I installed the Beta version of Mint 20 some time ago and updated it over time.
However, for various reasons I decided to do a complete reinstall on a newly formatted partition.
The first thing I noticed was that the Boot Loader screen was different from the Beta version. I had heard that this was the case and was prepared for it. However I liked the Beta screen and decided to run with it even though it is a very trivial matter.
apt install --reinstall -o Dpkg::Options::="--force-confmiss" grub2-theme-mint
or if you have a HiDPI screen
apt install --reinstall -o Dpkg::Options::="--force-confmiss" grub2-theme-mint-2k
The second slightly more serious problem I had discovered in the Beta version – Shutter is no longer available in the repositories. It’s a screen-grab programme that I had been using for years and would like it back. Fortunately I found an excellent solution over on Linux Uprising –
sudo add-apt-repository ppa:linuxuprising/shutter
sudo apt-get update
sudo apt install shutter
Enjoy!