Yes, this is the Last Available update to High Sierra after the November 2020 Security Update.
If you really mean UpGRADE to newer version of macOS - that is a different matter. Be aware before attempting to upGrade. The Age of this computer will govern what newer vision of macOS it Qualifies to upGrade to. About this Mac will provided this very important informations.
How to get old versions of macOS - the Links in the following page will require you to verify what version of macOS your computer can upgrade to. Once you have done that, Using Only Safari - commence the download of the qualifying macOS.
Notations: Make a Time Machine Backup Before attempting the upgrade. Mojave is the Last version of macOS to Still Support 32 bit applications, extensions and Drivers. Catalina and above Only Support everything 64 bit and Nothing 32 Bi - there are not workarounds for this.