### Description of problem: Current implementation does not support update operation during rolling upgrade and it cause data inconsistency. Please add a feature to support for update operation during rolling upgrade and avoid data inconsistency between source cluster and target cluster ### How reproducible: Anytime when update operation occurred on both source cluster and target cluster during rolling upgrade. ### Steps to Reproduce: 1. Configure JDG as noted in https://access.redhat.com/documentation/en-US/Red_Hat_JBoss_Data_Grid/6.6/html/Developer_Guide/chap-Rolling_Upgrades.html then start new Target Cluster 2. Configure clients to point to the Target Cluster, and one by one, restart each client node At this moment: - ClientA remained pointing to the Source Cluster - ClientB changed to point to the Target Cluster 3. ClientA get(KEY1), then VALUE1 was returned from the Source Cluster 4. ClientB get(KEY1), then VALUE1 was returned from the Target Cluster 5. ClientA put(KEY1,VALUE2) to the Source Cluster 6. ClientA get(KEY1), then **VALUE2** was returned from the Source Cluster 7. ClientB get(KEY1), then **VALUE1** was returned from the Target Cluster ### Actual results: Update operation on the Source Cluster does not propagate to the Target Cluster. The two clusters return different values. ### Expected results: Update operation on the Source Cluster propagates to the Target Cluster. The two clusters return same value.