This script allows you to create a button in the interface or create a shortcut to automatically save the file to the lower version for 3ds Max.
For example, if you have a 2014 version, the script will save in 2011.

Works from 3Ds Max 2012.

It is installed as a regular script, just DragDrop script in to viewport.
Then find it in Customize - Customize User Interface, choose Category: [3DGROUND] and assign hotkeys for Save To Lower.

Best keys combination Ctrl+Shift+S !