mintupgrade tool available on 20.3 explicitly?

[kmitz6]

I realized that I'm running Mint 20.1 when I tried to follow the guide but I was stuck reviewing my repository list because mintupgrade package was not available for me. I am not sure if this applies only to 20.1 or any other release too.

IMO, the first sentence - "This page explains how to upgrade from Linux Mint 20.3 to Linux Mint 21." can be interpreted as a requirement or an example. If the path applies to 20.3 explicitly, the doc should say that user needs to upgrade to 20.3 first.