Post: #2

You can find the source code on github. Probably build 2668 is from sphere 56c, so you must click on the button to switch to 56c branch and follow the guide to compile it
https://github.com/Sphereserver/Source

PS¹: the readme guide from 56c is outdated and doesn't have linux instructions, so you can use the current 56d readme guide (but installing mysql 5.6 instead 5.7 because sphere 56c uses mysql 5.6 libs)

PS²: 56c and 56d are quite similar, I can't remember exactly but maybe you can move to latest 56d build just updating some few base scripts (like sphere.ini, sphere_defs.scp, spheretables.scp and sphere_msgs.scp). So maybe it would be better update your server to latest 56d instead try to get an old 56c build