[Answered] Best way to work on multiple Minecraft versions for a mod?

I have a question for the more experienced modders that I've really been meaning to ask. as the title says, what's the best possible way to work on multiple Minecraft versions for one mod? let's say for example I made one for 1.15.2, but I wanted to let it support 1.16.5 and​​​​ I'll still work on the 1.15.2 versions. so that when I release it, I would release both editions and thus it would look similar to this:

• ExampleMod v1.0.0 (for 1.15.2)
• ExampleMod v1.0.0 (for 1.16.5)

I want to work on both versions, and I wanna know how you can have the same mod elements between the two workspaces.  or, is there a better way than that? I've been scratching my head for long, trying to find out how I could do this but somehow I can't wrap my head around it. so what's the most efficient way to do this?

thanks in advance! :)