Are you referring to this?
https://www.heroscapers.com/communit...ad.php?t=16931
I tried some add-ons but they didn't work. I haven't tried this yet, but if you search "Simple solution to use FLASH after January 12 2021" there is a portable version of Firefox someone made that might work for you. Since it's portable, you can simply delete the folder it's in and it's completely deleted from your computer. If you already have Firefox on your computer, just close that current version before opening this one.