private AbstractShortAssert<?> validate(final MemberData memberData) {
    return assertThat(memberData.getVersionOrdinal()).isEqualTo(unknownVersionOrdinal);
  }
MemberData has to be able to hold an unknown version ordinal since, during a rolling upgrade,
we may receive a MemberData from a member running a future version of the product.
geode-membership/src/integrationTest/java/org/apache/geode/distributed/internal/membership/gms/GMSMemberDataVersionJUnitTest.java