I just went through this in March or April. I went back and forth on whether to accept it or not. I really don't want any new accounts on my file. But an upgrade sounded good too. Ultimately decided to not accept. Really trying to sit tight till middle of next year. Want to grow what I have.
Well, Got an email last night saying I'd been upgraded and make sure I activated new card by Sept 30th. Not even sure if this time it's optional or not.
Guess I'll be watching the mail.