Here is the starting point for release notes: And a direct link to the April '19 release notes:

Let me just point out a few areas of particular interest for D365FO developers and the likes. I don’t have more details, than what’s in the document. I guess that not all these features are ready from April, but something we should see later during spring and summer.

Remote desktop access will be disabled for, at first, Tier-2 to Tier-5 environments. You will however get a way access the Azure SQL database for an environment.

New customers will not be able to host development machines on the Microsoft managed Azure subscription. Tier-1 environments managed by Microsoft will be test and configuration environments only, with no remote desktop access. Development environments must be deployed to the customer’s Azure subscription. We will however also see possibility to do development on a local machine and it will be possible to work on more than one application from the same environment.

The build automation framework will run directly on Azure DevOps build capabilities. We will no longer have the requirement of a dedicated VM to act as a build server. A build that is a release candidate can be automatically uploaded to LCS and automatically be deployed to sandbox cloud environments.

The release task for uploading a built package to LCS is already released. Check out these links:
First Azure DevOps Task Released!
Azure DevOps Release Pipeline