On Wednesday April 11th 2018, our old images.contentful.com and assets.contentful.com CDNs will be reconfigured to redirect requests to the new images.ctfassets.net and assets.ctfassets.net domains. This work completes the previous related maintenance [1]. You can read more about this change and whether it may affect you in our December blog post:
https://www.contentful.com/blog/2017/12/08/change-of-the-contentful-asset-domain/
Q: Is there anything that customers need to do to prepare for this change?
As described in the post, the old Asset and Image URLs will carry on working as permanent redirects to the new ones. In the majority of cases you shouldn't have to do anything. Customers using additional security measures such as outgoing proxies or Content Security Policies should review them to ensure they accept ctfassets.net URLs.
[1]
https://www.contentfulstatus.com/incidents/53z40hqw6qnv