AS3 with CPPSCreator is possible. You can use an AS3 Client for it. Or get the files from Solero, 2014 AS3 Files should work.
Once you got your files, head to https://cppscreator.com/
Sign Up, and when you do verify your email.
You should be redirected to your panel.
Press Manage Rooms and start uploading.
Disclaimer:
I will be making a full YouTube tutorial soon.
I followed my own steps and made:
https://insanegd.tk
(Sometimes servers are down cus CPPSCreator.)