Here at Google, the engineers love to add new features to the Maps API. In order to get these features in your eager coding hands as fast as we can, we currently update the Maps API about every two weeks. This breakneck pace is ideal for those of you that want the latest and greatest enhancements that we can offer. But some of you may prefer a version of the API that changes less frequently, so that you can be sure that newly introduced features don't affect the behavior of your maps application in unexpected ways.
Starting this week, we are offering a "stable" version of the Maps API that will be set to a version of the API that has been thoroughly tested over the past several weeks. You can point your application to the stable version to avoid the biweekly updates we do with the standard Maps API versions (v=2, v=2.x). We'll then update the stable version every few months to another version that is also well-tested, but includes the new features that have been launched. Once we release a new stable version, your application will automatically begin loading the updated set without making any changes to your code. But don't worry, we'll pre-announce any updates to the stable version so that you have adequate time for testing.
The stable version is currently set to 2.73, which was released earlier this year. Please be aware that version 2.73 doesn't include some of the latest features such as driving directions, KML/GeoRSS overlays and the traffic layer. For more information on the changes that have been made since version 2.73, please see the list on the Google Maps API Group page:http://groups.google.com/group/Google-Maps-API/web/api-version-changes