There have been many versions since Moneydance 2015 i.e. 2017, 2019, 2020, 2021 & 2022.
I'm really surprised you have been using the 2015 version on Big Sur without problems, we generally see various problems with older versions of Moneydance on more recent releases of macOS, the recommended minimum Moneydance version is 2021.1 for this release of macOS.
You can upgrade to the latest release and receive a 50% discount by using the upgrade field on:
Ethan on 01 May, 2022 10:26 PM
Just to add to the above comment: if your current version is meeting your needs, you do not have to upgrade. I too am surprised that you can run such an old version on Big Sur, but we have seen some instances of this.