Google announced that they’ve updated the Google Shopping Products feed specification. This update gives merchants and advertisers more refinements and options when specifying their product data in their feed.

Specifically there are new attributes where you can define bundles and mobile landing pages while making changes towards image quality requirements and landing page policies.

Here are the updates:

Mobile landing page links should be submitted separately to direct mobile shoppers to the right experience
Merchant-defined custom bundles, such as a camera with additional case and lens, must now be identified as such in order to be displayed appropriately on Shopping
Apparel attributes are added to allow more detailed descriptions of your apparel products
Item availability now simplified to allow a clearer distinction between different availability states
Mandatory character limits clearly stated for each attribute to help the right product information being displayed

This new feed specification will be required and enforced on September 30, 2014.

Forum discussion at Google+.