Version 1.5.3 released

Major changes:

• Blobstore API - no limit on upload size
• List of Indexes - programmatic access to the list of indexes and their status
• Datastore Admin - can be enabled from the admin console
• Memcache API for Python - now supports CAS operations
• Java Updates - using the AppCfg download_app command, you can download any files downloaded from the application directory war

Details below ...

Java and Python API extensions

Blobstore API : added size limit removed. Now you can upload files of any size, which allows the application to work with images, videos, etc.

Data store

• List of Indexes : added the ability to programmatically obtain a list of indexes currently assigned to your application in the data warehouse, as well as their status.
• Datastore Admin : Now you can enable the data warehouse administrator feature from the admin console. This will allow Java developers to use this feature to remove all subjects of a particular kind, without having to download the Python version of their application. And Python developers no longer need to define this in the app.yaml application file.
• HRD Migration Testers : looking for volunteers to try the improved HRD migration utility. Details in release notes.

Python Updates

Memcache API : now supports CAS (compare and replace) operations. This API can be used to update the value in Memcache only if only there are no other update requests between the time the value was read and the moment you are going to update it.
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Java Updates

Download the application : using the AppCfg download_app command, you can download any files downloaded from the war directory of the application during the last update.

More information can be found here:

Java release notes
Python release notes

Source: App Engine 1.5.3 Release