[CentOS] mounting an nfs4 file system as v4.0 in CentOS 7.4?

Thu Sep 28 21:18:03 UTC 2017
Zube <Zube at stat.colostate.edu>

CentOS 7.4 client mounting a CentOS 7.4 server filesystem over nfs4.

nfs seems to be much slower since the upgrade to 7.4, so I thought it
might be nice to mount the directory as v4.0 rather than the new default
of v4.1 to see if it makes a difference.

The release notes state, without an example:

"You can retain the original behavior by specifying 0 as the minor version"

nfs(5) states:

Recent kernels allow the minor version to be specified using the
vers= option.  For example, specifying vers=4.1 is the same 
as specifying vers=4,minorversion=1.

but in fstab or on the command line, using either form (vers=4.0
or vers=4,minorversion=0), if I run mount afterwards, I still see
vers=4.1 for the mount.

I'm missing something obvious, but the only thing obvious to me
is that I can't see it.

Any help is greatly appreciated.