"old world" charm level cap

[Finias]

I did play an enchanter on live and I do remember there being an old world limit on charm and mez.

This was only really relevant in hate/fear (rarely) and in the hole (somewhat more common with the golems and ghosts). Plane of air was on kunark rules, so boltran's and dictate worked fine there.

Unfortunately I don't remember the exact level cutoff, but my suspicion is this level cutoff is based on the allure level cap since that was the highest level charm spell in the old world.
51 and lower - charm can land
52 and higher - charm will resist (I don't remember if the resist message actually told you why it bounced initially or you just got resists.)