Speaking of backwards compatibility

Replying to a question in the Notes 9 forum, the excellent John Paganetti wrote this

"In our Notes Development Domain I have Domino Servers running 6.5.6FP3 (1), 7.0.4FP2 (1), 8.0.2FP6, 8.5.3FP4 (30+), 9.0 (30+) all running with Domino 9.0 Directory Design....   Being accessed by a variety of Notes Clients (8.5x and 9.x) and iNotes Users...

If you find any problems, I would be very interested in knowing about them...  I am not aware of any...."

Now, Domino 6.5 shipped 10 years ago, and is still compatible with the latest version of the product. Try this with Exchange......