It would be nice to change the way this works:

• On the "Registration" screen, Do not request a username, enter a random user ID instead. (Subsequently, in the user's profile, being able to change the user's name, the user's id would not change, just change their name)

• This way the name could be edited in the user's profile and the new name would be shown to all contacts.

• Eliminate the option to rename contacts, instead, you can assign an alias to your contacts, without losing the real name (Show the real name in the contact profile).

On the other hand, in the "Registration" screen.

• Keep the option to enter a password.
• Add a button to generate a random password (and show the generated password).