High & Late Campaign?

[Basileus of Byzantium]

I'm installing this submod again after a few years and feel an itch for the high campaign however if I remember correctly, I remember hearing that the mod was complete for the Early Campaign but not the High & Late. I don't recall anyone mentioning anything specific except that some "features" weren't implemented. If I were to play a High campaign what would be missing compared to an early one?

[Lifthrasir]

The high era campaign is basically just at a beta stage (to not say even alpha). It works but it is not accurate.