3 years later, I now want to play Sevtech Ages - this means that I need to update all of my mods to the current version.
Here's Armour HUD v3.2 for Minecraft 1.12.2. It's tested and working with vanilla durability and IC2 equipment, mainly because I have them in my build environment. RF-powered items should still work unless they broke something massively behind the scenes (beside a small classpath change for the API which I've already noticed), likewise for Tinkers' Construct items (though I can't remember how well they worked before). I can't test these because I haven't got something that'll work in a deobfuscated dev environment.
New is support for Forge Energy-powered items, which should also work fine (it's basically RF), but I likewise haven't tested that out.
Known bugs: whenever the annoying little achievement thingy pops up in the top right hand of the screen telling you "you've picked up cobble, congrats, there are new recipes", the text display spazzes out and shows blocks instead of letters. I have no idea how to even start to diagnose this - sorry
I have yet to feed this to an actual modded setup that isn't a dev environment (haven't begun that Sevtech playthrough yet, waiting on the other players to arrange a time), so I can't say much about how well this .jar will work in real gameplay. Tell me if you use it and something goes horribly wrong.