Thank you for contacting us.
As you mentioned, you didn't saw any improvements that were implemented from the 2015 year. Please check this article https://www.opencartmanager.com/discover-the-latest-updates-of-store-manager-for-opencart/
According to it, you may see what improvements were implemented during the years. Near the page, you will see all the versions we released up to the latest and what was done in that versions.
Wishing you a good day!