We will update available versions of the Maps JavaScript API during the week of August 14th. The versions will then be:
Weekly channel will serve 3.54
Quarterly channel will serve 3.53
Exact version numbers can be specified as v=3.54, v=3.53, v=3.52, or v=3.51
Version 3.50 will be decommissioned.
If you don't specify a version (or request a retired version), you will be served a default version, which depending on your key configuration will be either 3.53 or 3.54. But a developer specified version will always be honored and served when requested when it's an existing version.
For more information about Maps API versioning, see:
https://developers.google.com/maps/documentation/javascript/versions
To report issues with any version of the API, see: https://issuetracker.google.com/savedsearches/558438