Rhino 6 .3dm file won't open in Rhino 5

Small file… nothing other than basic 2D line drawings and a couple of layers.
Saved as 3dm file on Rhino 6, but won’t open on Rhino 5 saying the following:

“Error
The file (file name) was created by a newer version of Rhinoceros.
This file cannot be read by Rhino 5.0
For information about the latest version of Rhino visit (rhino3d.com)”

  1. Can I somehow convert the file right now using the Rhino 5 computer?
  2. For the future when working from home on Rhino 6, how can I save the file so it can be operable on Rhino 5?

Thanks

Save As then select v5 3dm.