I confirm d.roger 's words but I recommend parasolid as an export format. In addition, SW has never given the possibility to save in a lower version (too much risk of bug depending on the version).
The only possibility offered was to be able to open the files of the major version N+1 with the SP5 of the major version N-1 but on the one hand we only see a dead body and no possibility to open the drawings.
You can save your assembly in STEP and then use Featurworks when opening your parts. This function allows you to recreate the construction tree with the functions available on the version you are working with on the computer.