Uddeim change username to email

Hello,

I use Uddeim and I would like to config that users can fill in an E-mailaddress in stead of a username in Uddeim when they send an message.

I know that I can edit the file includes.php, but I don't know which line!

I am sorry, it is not that easy. UddeIM works internally with user IDs, so you have to find the correct user ID for a certain email address. Currently there is also no field for that and it does not work to use the existing variables for that purpose since these are also used for other functions.