Original AoM:TT allowed to use modified _anim.txt files online. Sadly AoM:EE tag all _anim.txt files as desync sensitive and wont allow them in online matches.
For that reason Xentelian’s Unit upgrades wont work online.
I found that there has been some efforts to fix that.
"Anim Sync Checker
WarriorMario is working on a program to distinguish sync-breaking anims and BRGs from harmless ones, which would drastically reduce the number of “desync-sensitive” tags in the Workshop. This would allow a lot of harmless anim mods to be used online, which has been a major concern for the online community. Feel free to contact him in order to discuss his code."
Any info if there has been any progress?