RT::Authen::ExternalAuth and multiple e-mail addresses

I am currently running RT 4.2.12 and I’m looking for a way to handle multiple e-mail addresses for a single LDAP user with the RT::Authen::ExternalAuth module.

Specifically, we are facing an issue when a person’s RT user record was originally created with one username/e-mail address pair (e.g. JSMITH1, JSMITH1@domain.com) and the user then changes their primary e-mail address (say, to jane.smith@domain.com). Next time they submit a ticket via e-mail to RT, the ticket is rejected with an error message stating that “RT could not load a valid user” because RT looks up their e-mail address in LDAP and sees the username collision with the existing RT user record.

I am aware of the multiple-emails branch of RT::Authen::ExternalAuth (https://github.com/bestpractical/rt-authen-externalauth/tree/multiple-emails) and I’m considering that as a potential solution, but I’m curious if there are any better options, or if there are any plans to merge that branch into the master.