NRT may or may not still work in 4.0; it was the most reliable of raid tracking mods like this in 3.x. HeadCount's unreliability in recording made it a no-go here after testing the last few versions.
But if NRT does not still work, sRT looks like a good, actively developed 4.0 replacement. The author took the NRT base and converted it to use Ace3 instead of Ace2, etc.. Uses a LDB display & tooltip instead of FuBar and so on.
Its still missing a number of features of NRT. But the author seems to be actively adding them. In the single raid trial of it here in WoW 3.x, it worked without errors and accurately recorded both the all the loot drops and attendance on all bosses through the first 7 in ICC25.
Gave srt a go tonight, missing stuff I use in Headcount such as editing who got an item, adding items, adding cost and it also seems to make every single boss kill a different raid which isn't the way I add kp to our eqdkp site, tend to do them all at once.
not sure there are any alternatives out there atm ;o
Yah, but most of that (except notes) was not in NRT either; only HeadCount. Made no difference here, but others may miss HeadCount's features.
As to "editing who got an item, adding items, adding cost", you can edit notes with sRT. As to NRT, I did the basic replacement of this with self in the last r141. Afterwards, it does not bug out anymore on load or accessing saved data. As to whether its fully functional in raids, still to be determined (have yet to raid in 4.x...heh).
Not sure how much you intend to expand headcount, but having the ability to add loot manually would be hihgly appreciated, sometimes people pass thru the doorway after Saurfang or move too far away after bloodqueen/putricide and the loot isn't tracked .. adding via the command line is a little qawkward to explain to new people.
But of course, an ace3 version of what we got now is more than I was hoping for :)