AMP Cache Updates

In December 2016, Google announced an update to the domain scheme of the Google AMP Cache, where each site would be served from its own subdomain of https://cdn.ampproject.org to enhance security through the HTML5 origin model. This change requires AMP publishers to update their CORS implementations to accommodate new subdomain patterns, which will eventually replace existing URLs, though these will still be supported and redirected for the time being. Subdomains will be human-readable, closely resembling the publisher's domain, unless technical limitations necessitate a one-way hash. Publishers and service providers like ads and analytics vendors need to adjust their systems to accept requests from these new subdomains, while Google Search plans to adopt this new URL scheme promptly and offers a testing sandbox for developers to ensure compatibility and address any CORS-related errors during the transition.