As of 2.4 DamageMeters will no longer be updated by AnduinLothar. He was not the original author but had picked up maintaining it. 2.4 has some significant combat log changes and has decided it is too big of a job to maintain it.
Some more info and alternatives are suggested here,
DamageMeters and 2.4 - Cosmos UI for World of Warcraft
I will be testing some of the suggested alternatives.
AnduinLothar discontinuing Archaeologist as well, however it will be replaced by a complete rewrite, most of the current functionality returns however split into a couple of different addons called UnitFrameBuffs and UnitFrameTweaks to make it more modular.
For Cosmos users, no devs were able to test on the 2.4 PTR, but most addons should work ok so the update might be a little slow.