Is there any advantage to upgrading switches to v6 from v5 with cnmastro ?
I think v6.1.1 is the first release to support a new line of switches. The second release, v6.1.2, just added some small bug fixes to the first release. You can run v6 on all cnMatrix switches. You should review the release notes and see if there are any fixes in v6.1.2 that apply to you.
I strongly recommend upgrading the switches to 6.1.2.