Ok, the usual rules apply...........as long as you don't use any V16 features, this should work.
The file needs to be opened in V16 and then saved as a .L5K file.
Then open the file in a text editor and change the line that says "IE_VER := 2.7;"
Change the 2.7 to 2.6 and then save the file and exit.
Open your V15 software and open the L5K file and import it as a V15 app.
OG