r514 is not available in the update section because it's a testing version. When the new features added in the test release are confirmed to be stable, Gene will either migrate the version to the main line and create an update or do so with the next minor update. Testing releases generally have larger inclusions that could cause issues for some users and thus are not considered stable.
If you want to try the testing releases, you can find information about them in the BUG REPORTING -> Re: TESTING RELEASE topic. Be aware that some of these versions can cause problems/unpredictable activity. It is not advised to use such a release on a critical system.