Im not sure but You can cheack this :
# ---------------------------------------------------------------------------
# Misc Player Settings
# ---------------------------------------------------------------------------
# Character name template.
# Examples:
# CnameTemplate = [A-Z][a-z]{3,3}[A-Za-z0-9]*
# The above setting will allow names with first capital letter, next three small letters,
# and any letter (case insensitive) or number, like OmfgWTF1
# CnameTemplate = [A-Z][a-z]*
# The above setting will allow names only of letters with first one capital, like Omfgwtf
# Default .* (allows any symbol)
CnameTemplate = .*
# This setting restricts names players can give to their pets.
# See CnameTemplate for details
PetNameTemplate = .*
# Maximum number of characters per account.
# Default: 7 (client limit)
CharMaxNumber = 7
from server.properties