Hi,
I checked the interoperability matrix, this is what it suggests.
VSC 6.2.1 = Reached End-of-version-support
It is compatible with up to maximum version ESXi 6.5 (Update 1)
Therefore, upgrading to ESXi 6.7 will most likely break it or would NOT be supported.
For ESXi 6.7 you will need to upgrade VSC to minimum : 7.2.1 and the minimum supported ONTAP is 9.1
In anycase : The curernt VSC is end-of-version-support, so it makes sense to upgrade both VSC and ESXi.
Thanks!