Yep, his contract ended and he decided not to renew it. Also, Ryeowook and Heechul and sent support messages for him wishing him all the best in whatever he chooses to do in the future
I love Kibum, he's still my second bias, but it's not surprising at all, we all knew that the music world wasn't what he trully wanted. If anything I'm glad he left so peacefully, he just stopped promoting and waited quietly for his contract to end while performing a couple of acting roles, without scandals and or surprises. I hope he's happy in whatever he chooses to do in his life.