Current VR versions generally require matching major version of vCenter. For example - if vCenter is upgraded to 6.5, then VR must also be upgraded to 6.5.
The interop matrix can be checked at VMware Product Interoperability Matrixes
Please note that current VR versions also require matching major version at source site and at target site.
Underlying replications will continue during upgrades, but management functionality will be restore only after the major versions match across the source site and target site and between VR and vCenter.