I remember someone saying "We have been best friends for 15 years", and another person pointed out "No, 15 years ago you were best friends"
People change, and sometimes you have to leave those friendships in the past. Do the small talk and catch up when you do come across each other, and reminisce.
Years ago a couple had asked us to stand for them at their wedding. We thought about it for a week, and finally had to tell them NO. We did not consider ourselves close enough friends to have the honor bestowed upon us.