If, for example, a flag is listed as deprecated in 10 and obsolete in 11 and we simply switch the version to 11 without actually obsoleting the flag (ie removing it) we get a VM warning in debug builds as a reminder that this needs to be done eg:

Java HotSpot(TM) 64-Bit Server VM warning: Global variable for obsolete special flag entry "FastTLABRefill" should be removed

This was considered a good thing to do to ensure we didn't forget to do the obsoleting or expiration. In practice it is causing problems as we prepare to go to version 11 because, unfortunately, there are many tests that can not tolerate unexpected warnings in the VM output and will fail. While many of these have been fixed (for tier1 and tier2 test groupings) there are still a number of fix for tier3 and above, and it is simply taking too long and delaying the version update.

So as a temporary measure we will simply disable these transitional warnings so that the tests pass. Bugs will also be filed against those tests so this is not an issue in the future.

Note that if you actually use an obsolete flag you will of course get a warning about that.