I was about to release the program once complete and make it a surprise to everyone, but oh well... I'm working on a C++ 1.24 to 1.23 level converter. Currently I have made it to decompile and recompile J2L's. Now I have the task of figuring out the structures of the 4 data streams and the differences between 1.23 and 1.24. If anyone feels like contributing the knowledge, I'd greatly appreciate it. Neobeo, can you update your J2 File format specs post with the latest findings every once a while?

Cheers.

EDIT: What I did tn that JCS patch is only disable the level version check. That's why it crashes often when there is unrecognised data inside the level.