Ubuntu – Mounting Windows Share using SMB 2.1 or greater

I am attempting to mount a Windows hosted SMB share (CIFS) using Ubuntu 12.04 (using kernel 3.13.0-117-generic). Mounting with SMB1 works, but that is not acceptable, we must instead mount with SMB2.1 or higher.

Below is the output from my attempts to do this by passing the ver= argument

root@----:/# mount -t cifs //SERVER/smbtest /mnt/smbtest --verbose -o ver=2.1,user=administrator
Password:
mount.cifs kernel mount options: 
ip=10.16.0.40,unc=\\server.domain.net\smbtest,ver=2.1,ver=1,user=administrator,pass=********
mount error(22): Invalid argument
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)

As you can see, there are two ver arguments in the mount.cifs kernel mount options, the one that I specified, and the default (1). This happens if I specify anything other than 1 or 1.0 for ver.

cifs-utils version 5.1 is installed, and cifs.ko is on version 2.02. From the SMB3 kernel status page on the Samba wiki, https://wiki.samba.org/index.php/SMB3_kernel_status,

"The minimum version for use of the Linux kernel SMB3 support is kernel version 3.12 (or backport of cifs.ko module version 2.02 or later) but kernel version 3.18 or later (or equivalent, ie cifs module version 2.04 or later) is recommended for best SMB3 support."

Can anyone help get me on the right track here? I must be missing something. What other methods are available to force SMB2+ connections? This is my first post here, and I tried to keep it brief, if I missed anything let me know and I'll add the info to my post.

As far as I can tell this should work, though I wouldn't be surprised if I have misunderstood something and SMB2+ isn't supported.

Thanks

EDIT: I understand 12.04 is EOL. I will update this post tomorrow with the relevant info for 14.04, which has the same issue. If anyone can answer re: 12.04, that would still be appreciated.