MyBB Community Forums

Hi all
How can I disallow all latin characters in usernames, [a-z][A-Z]
and allow only arabic characters p{Arabic} like أ ب ـ جج ح....etc
I want also to ensure that usernames incluse at least one alphabet, this to disallow usernames consisting of numbers only, like: 12358
When I was using phpbb, I used the following function to archeive the two requirements:

$regex = '[\p{Arabic}0-9-[\]_+ ]*\p{Arabic}+[\p{Arabic}0-9-[\]_+ ]*';

This was my best anti-spam weapon !! spam bots seem not able to use arabic keyboard
How can acheive those requirements on mybb?
Thanks

Well, at least, is there any way to ensure that username contains at least one alphabet, so usermanes with mere numerics like 55555 or 12345 .. are disallowed?