While appearing in this drama, I learned about sisterhood and thought a lot about the [After School] members. The members were basically like my sisters,” began Park Soo Ah. “I met up with Jung Ah. She’s currently five months pregnant with a son. It felt weird to see her stomach and her becoming a mom. She wouldn’t drink soda, and it felt odd.”
She continued, “The members sent me coffee trucks when I worked on dramas. They congratulated me after I turned into an actress and got bigger roles. We still have a group chatroom, so we still talk and and chat a lot about all kinds of things. Sometimes when I watch clips, I think about how it was really tiring but great [during After School promotions]. It reminds me a lot of the past when I see idols promoting these days.”
“Later, I want to go on a variety show like ‘Sugar Man’ with the members,” said Park Soo Ah, referring to the JTBC music variety show where currently popular singers perform covers of classic hits by singers from the past, who also appear on the show to update fans on what they’ve been up to. “I think a lot of time will have to pass. Among ourselves, we thought about releasing an album. We thought it wold be good to gather opinions to release a final album and end [promotions], but it’s sad that it didn’t work out because we all went our separate ways.”
She added, “The members also tell me about my drama’s viewership ratings. We used to all go to the hair salon around the same time. We’d wish each other the best for the day and cheered each other on to gather strength.”
https://m.entertain.naver.com/...
So basically after school unofficially disbanded.
AS adopted the graduation system in hope of developing a "long-lasting" group. But it ended up as one of the main factor (another bigger factor will be the fact that they're in a bad agency) that led to their miserable disbandment.