From 5.7, we have introduced a new endpoint for streaming assets. The old API is still available, but has been deprecated.
The new asset urls are accessible on the following urls
http(s)://<api-url>/digizuitecore/LegacyService/api/assetstream/{assetid}
http(s)://<api-url>/digizuitecore/LegacyService/api/assetstream/{assetid}.{extension}
http(s)://<api-url>/digizuitecore/LegacyService/api/assetstream/{assetid}/{mediaformatid}.{extension}
Additionally as part of the accesskey logic change, the accesskey has also been reworked for streaming assets for higher security.
The asset urls now contains a signature which is an accesskey token generated from the combination assetid, format and the user requesting it.
This means that the same signature from one user cannot be used to access another users assets, despite the assets being the same as the identity is encoded in the signature.