I don’t know if this is exactly the best place to put this, but I didn’t see a better place, so sorry in advance if this isn’t the correct forum. I’m wondering what the requirements are of a Display ID (ie, Kryptik.8093 for my account). I’ve seen people with arbitrary spaces, varying lengths, and capitalization, but no unicode.
What are the minimum and maximum lengths ( without the unique .####)?
What characters are allowed?
I’m asking for validation on a guild website so that we can make contact with applicants whether they are online or offline via Mail. You cannot send mail to a n offline character name, and an incorrect display ID wouldn’t do much good either.
I could not find this information anywhere else or I would not ask the; not the wiki, not any other faq page or any community driven site. I’m assuming I should probably put this on a wiki page, if I can get the answer here.

Knowing the “ID requirements” is irrelevant; you either know the name or don’t know the name. For example, knowing that # is allowed or is not allowed in a Display Name isn’t relevant. Knowing that a name contains # is the important factor, and you’ll know that when you interact with a person whose name contains that symbol.