Has NFS changed recently?

[John <jpff@codemist.co.uk>]

I run a mixed Debian/openSuSE /android LAN an after an upgrade of one
component from jessie to stretch I have hit a big problem.

Mail is delivered into a mbox on the Debian server, and the disk is
mounted on the user machine via NFS so the mail can be read into emacs
from a simple file.  This has worked for many years.  But now with the
jessie->stretch upgrade it fails with emacs barfing.  I know that the
emacs did not change so I am guessing that the issue is with NFS.  Any
possibility of this?

==John ffitch