The song is called Memories, by the artist salaisuuxia.
A while ago, I wanted to replay Acting Lessons, after having completed version 1.0.0 back in the day. Now I knew that some songs were swapped due to copyright issues, however comments here on this forum led me to believe that there were only minor changes to the soundtrack, that you would barely even notice. No big deal, right?
Imagine my surprise when the ending song was replaced! 'Memories' was such a beautiful, emotional and fitting song to conclude this story and play during the end credits. I'm surprised nobody ever brought this up and no music restoration mod exists for Acting Lessons.
Personally, I consider 1.0.0 to be the preferred version of AL. V1.0.2 might have some bug fixes, but honestly I never came across any bugs before. As far as I can tell, one obscure ending can't be reached in v1.0.0. Oh well...
Speaking of, I feel the same way about version 0.8.2 of Being a DIK Season 1 & 2, since a significant part of the soundtrack has been removed on the 'final' version.