private VM rollServerToCurrent(VM oldServer, int[] locatorPorts) {
    // Roll the server
    oldServer.invoke(invokeCloseCache());
    VM rollServer = Host.getHost(0).getVM(VersionManager.CURRENT_VERSION, oldServer.getId());
    rollServer.invoke(invokeCreateCache(locatorPorts == null ? getSystemPropertiesPost71()
        : getSystemPropertiesPost71(locatorPorts)));
    rollServer.invoke(invokeAssertVersion(VersionManager.getInstance().getCurrentVersionOrdinal()));
    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