This is a table to make a fast relationship between your current VMBUS.SYS version and the corresponding Hyper-V level.

Remember to upgrade the ICs of your VMs after applying any of this updates to your hosts.
HYPER-V IC VERSIONvmbus.sys
W2K8 RTM6.0.6001.17101
W2K8 RTM + Hyper-V RTM (KB 950050)6.0.6001.18016
W2K8 + KB 9567106.0.6001.22258
W2K8 + KB 9599626.0.6001.22352
W2K8 + SP26.0.6002.18005
W2K8 + KB 9759256.0.6002.22233
W2K8 R2 RTM6.1.7600.16385
W2K8 R2 + KB 9753546.1.7600.20542
W2K8 R2 + KB 9818366.1.7600.20683