I just found a divorce letter addressed to my boyfriend and his ex. Does that mean it was recent?

Okay, so I'm no expert on legal terms and matters of the court. In fact when I picked up the letter, the only reason I knew it had to do with a divorce is because it said petitioner and respondent in the case of the marriage between them. My boyfriend avoids the subject at all cost, about his daughters and his ex wives. However he has given me enough information to lead to believe they hae been divorced for some time now. So my question is, will the courts send a letter to someone divorced asking them to mail in a signed form that late? Or does that mean the divorce was more recent? She was the petitioner and he was the respondent. If it was just filed recently by that date, then that means that he never filed for a divorce and that he basically lied to me. I plan on asking him myself. I just want to know what the hell I'm talking about.