What happened with Charlotte?

With Frasier leaving Seattle to join Charlotte in Chicago at the end of the series and now picking up the reboot in Boston, we have to wonder how his relationship with Charlotte played out. Laura Linney not returning doesn't bode well for Frasier's love life. I have to wonder whether Charlotte will be written out at a love affair gone cold, killed off, or (unlikely) given the Maris off-screen treatment.