For multisite cluster indexer environment, Can site1 indexer on 6.5 work with site2 Indexers on 6.4?

I am planing an splunk upgrade, master and SHc are on 7.0 but next step is to upgrade Multisite Indexers cluster, since We are critical on downtime, All Indexers are at same 6.4.* Can site1 indexer on 6.5 work with site2 Indexers on 6.4 ? Final goal is to bring them to 7.0.