Default value
0
Sometimes when transitioning between BYOND versions you’ll want to keep a savefile in a condition where it can be read by older versions. The byond_version var tells it to avoid using newer savefile features (unless forced to) above a certain build number. (The build number changes more often than the BYOND version number.) A value of 0 means not to worry about it.
This can be changed on a per-savefile basis so that you can use newer features in some files and avoid changing others. For instance, character saves might want to go on using older features for a while, but for saving parts of the map you might prefer to allow newer features to be used.
The default savefile compatibility version can be set at compile-time:
savefile/byond_build = 1600 // do not use savefile features from BYOND build 1601 onward