major.minor
where major and minor are just plain integers (separated by a period). The major number is incremented when a symbol has some sort of a change which will break or might break an existing schematic. The minor number is only incremented when a cosmetic or very minor change is made to the symbol. The major and minor numbers are not coupled in any way, however, when making major version changes, the minor version number can be reset to zero.
If this attribute is inside of a symbol and that symbol is placed onto a schematic, then the symversion= attribute will be automatically promoted and attached to the outside of the symbol. During the load of the symbol from disk, the value of the symversion= inside the symbol file (if any) and the symversion= attached to the symbol (if any) are compared. If the values are the same then the placed symbol matches the disk symbol file, however if the values do not match, then libgeda will output a warning/error message (based on whether it is a major or minor version change).
New symbols should not receive this attribute at all. Only when the symbol is change should this attribute be placed into the symbol file and maintained. Users should not attach this attribute manually to instantiated symbols. This attribute should normally be made invisible when placed inside of a symbol file. This attribute is always promoted when it is found inside of a symbol (during component placement).
Examples: symversion=1.1
Ales Hvezda 2004-12-28