Recently I installed Linux Mint and used the software manage to install Sweethome 3D. The version installed was 4.3.
However, visiting the homepage of Sweethome I noticed that several upgrades have become available and the latest is now 5.2
I have downloaded the latest version and it will run when I click the program file in the download folder.

Question:
why is the software manager not giving the latest version.
how can I include this latest package in my Linus software menu.

Any suggestion is highly appreciated.
Paulus