Thanks for the reply. I was pointed to sk164212 as a possible option, which I believe you are referring too.
Multi-Version Cluster (MVC) replaces Connectivity Upgrade (CU) in R80.40 (sk164212)
In R80.40, Multi-Version Cluster (MVC) is introduced. MVC is a next generation upgrade method which replace the deprecated "Connectivity-Upgrade" (CU).
More information on MVC can be found in Check Point R80.40 Installation and Upgrade_Guide.
Check Point R80.40 Installation and Upgrade_Guide
Supported Versions in Multi-Version Cluster
The Multi-Version Cluster (MVC) in an R80.40 Cluster Member supports synchronization with peer Cluster Members that run one of these versions:
R80.30 (see sk144293).
R80.20 (see sk122485).
R80.10 (see sk111841).
R77.30 (see sk104859).
In an Multi-Version Cluster, the Cluster Members can run only these versions:
R80.40 and R80.30
R80.40 and R80.20
R80.40 and R80.10