I hadn't thought of that. I'll put it on the todo list to look into whether or not I can make it automatically reimport for the same file yet. I will probably have to request more sdk features for that to be possible. [Edit: Just looked into this. I probably won't be able to get to until after the next Spriter 2 milestone, but it looks like it probably won't require any additional sdk files afterall. I will know for sure once I get a chance to dig into it]
in the meantime, you can remove the old scon file, and import the new version in the project pane. If you're using a sprite atlas, you can load the new one in by double clicking the scml object. If you're using separate sprites, the order of where frames need to be imported requires the import in some cases, so there's not an easy fix for that. In those situations, the only workaround would be to import the new version, select all events with the old version of the scml object and the family and right click - Replace Object.