I happened to notice the typo.
https://github.com/aburch/simutrans/blob/0c45d1a60c3424f1828f596366a67870025a741d/dataobj/environment.cc#L502
if( file->is_version_atleast(120, 7) ) {
I think 120 is correct instead of 102.
Thanks for reporting! Not sure what to do. Fixing this typo might make some saves unloadable.
Only saves that were saved with a nightly between r8573 and release 120.4 r8588 will not be able to load default.sve... That is really not a issue, sicne the environment is not saved in the savegames. The environment is usually only read from the previous version during an update.