1.9.4 was surprisingly fast, compared to 1.8.9.
Then, astoundingly, 1.10.2 only had a few changes in the deobfuscation, so I tried the 1.9.4 build in a Minecraft 1.10.2 modpack, and it worked as-is!
Though I discovered an infinite loop bug in my brewing recipe discovery algorithm, so it took a while before I could look over it to be sure it was compatible. That's fixed, now.
perhaps make branches on github for post 1.10 versions that you can release as beta builds, one release each, while the main repository and releases stay on 1.10. Then when you're finally ready to move on, you can push the changes from the 1.10 (main) branch to the other branches, as well as also having later versions out that people can search for bugs and list them as issues that would either be fixed in the main branch already or that would need to be fixed for those specific versions. This would both allow players with newer modpacks/servers to use your mod and cut down on some of the time that you'd need to have a version out before you find bugs.
Sorry if that sounded slightly incoherent, it's been a long day already.
I'll have to look into how complex the changes are, and whether I can create a utility function to abstract the differences, but I've heard that there was a change from null ItemStacks to ItemStack.EMPTY or something of the sort, which would make merging changes (or even just updating a snapshot multiple times) a massive hassle. No idea how much complexity will come with advancements and recipe JSONs, though, so it might be plausible to make an abstraction for 1.11 but impossible to add 1.12, or it could be trivial to keep that in a backwards-compatible manner.