Former client reached out to share progress

Hi all! Looking for guidance here. I have bounced it around coworkers but I'm curious about other professional opinions. In a nutshell, last year I transitioned a client to another therapist due to their needs escalating out of my scope. This client reached out this week to share recent progress, basically conveying the successes they've had recently, expressing gratitude, etc. They did not request to return to services; the message seems more like a reflection on their progress. I'm curious how you all would respond to a contact like this?