VM rollServerToCurrentAndCreateRegion(VM oldServer, String regionType, File diskdir,
      RegionShortcut shortcut, String regionName, int[] locatorPorts) {
    VM rollServer = rollServerToCurrent(oldServer, locatorPorts);
    // recreate region on "rolled" server
    if ((regionType.equals("persistentReplicate"))) {
      CacheSerializableRunnable runnable =
          invokeCreatePersistentReplicateRegion(regionName, diskdir);
      invokeRunnableInVMs(runnable, rollServer);
    } else {
      invokeRunnableInVMs(invokeCreateRegion(regionName, shortcut), rollServer);
    }
    rollServer.invoke(invokeRebalance());
    return rollServer;
  }
This test starts up multiple servers from the current code base and multiple servers from the
old version and executes puts and gets on a new server and old server and verifies that the
results are present. Note that the puts have overlapping region keys just to test new puts and
replaces
geode-core/src/upgradeTest/java/org/apache/geode/internal/cache/rollingupgrade/RollingUpgrade2DUnitTestBase.java