[horde] Upper and Lower case and Horde IMP username

[George ccto]

Hello Horde User/support,

Recently, I found Horde webmail username is case-sensitive.

For example, if a user usually login as "xyz at abc.com" in the past,
then some day some time he inputs "xyz at ABC.COM"

Then, Horde will raise error as below -
'QUERY FAILED: Duplicate entry ???? for key 'rampage_users_user_name'

Even with admin account one.

Please help.

Thank you very much for your kind attention.

Regards
George.