You may remember a while ago that Airport Enhancement Services developer Oliver Pabst released a test version of a major update to AES, dubbed version 2.20. Now, as a result of that testing and with the faults in it fixed, the update has been released with some new airports supported and one updated, as version 2.21.
Alongside the most obvious visual changes of new models, a number of fixes and improvements have been implemented with AES2.21, but rather than try and list them here, if you want to know exactly what has changed, we suggest that you take a look at the release notes (pdf). The full list of airports now supported is available here and the new version can be downloaded, as well as credits for your new airports purchased, at simMarket, here.