If it’s an old therapist it could be that at the time they treated you they were not as knowledgeable and experienced at the time and may have a much better understanding now of the challenges you presented to them with. Just in the past five years alone more has been learned about different challenges. It could be that these individuals think about you when they learn more about the kind of challenges you have. So they are just contacting you to ask how you are doing.

It’s a good thing that you have gained on understanding and better managing your challenges.