If that post is correct, I don't see that option under Edit, maybe because it hasn't rolled out here yet, but I think putting the update under the Edit menu is a bad idea:You can upgrade to Linux Mint 20.1 from Linux Mint 20 LTS from within the OS:
Open Update Manager
Click Edit > Upgrade to Linux Mint 20.1 Ulyssa
1. This in an update. It should show up among the list of updates.
2. Menus are generally static. If I look at the Edit menu now and see "Preferences", "Snapshots" and "Sources", I have no indication that in the future I might find there... a Cinnamon upgrade.
3. If for some weird reason the Cinnamon update should stay in that menu, it should be greyed out when not available, so the user knows that's a possible option. (I personally would wonder why is it greyed out, which again goes to show that's not the place where there update belongs.)