arcgis 10.2 - Converting mxd to earlier version using ArcPy?

I am running arcmap 10.2.2 but need to open an mxd saved using 10.3. I do not have access to 10.3. I have an arcpy tool which will do the conversion but it is not working from within 10.2.2.

Does anyone know if it is possible to do this from within 10.2.2. I get an error message saying I do not have write access to the file.

The script is as follows:

import arcpy, sys, os, string 

mxdList = string.split(arcpy.GetParameterAsText(0), ";") 
outloc = arcpy.GetParameterAsText(1)
version = arcpy.GetParameterAsText(2)


suffix = "_"+ version.replace(".", "")

for item in mxdList: 
    item = item.strip('\'') 
    mxd = arcpy.mapping.MapDocument(item) 
    base = os.path.basename(item) 
    base = os.path.splitext(base)[0] + suffix + os.path.splitext(base)[1] 
    mxd.saveACopy(outloc + os.sep + base, version)
    arcpy.AddMessage(os.path.basename(item) + " has been converted")