The improvements are:
- Die with an explicit message when a user is trying to reset his lost password and the option is disabled in config
- Redirect user to main page after password change using relative URL
- Don't leak info whether user exists or has recovery info defined
- Throttle password reset requests to prevent brute force attacks
- Show phone/alt email fields in mailbox/admin edit form only when the password reset option is enabled
- Make database upgrade code compatible with other databases types
- Use the existing password generator to generate OTP. It is now stored in database, unique to each user, valid only for 1 hour and can only by used once.