If you are waiting for the Dynamics 365 9.0 version download link then you should read this article. Recently Microsoft has done changes in the release of documentation for developers related to Dynamics 365 development which was referred as SDK (Software Development Kit) earlier. Going forward there won’t be any single SDK file for download instead the complete documentation can be referred from here which will have complete developer’s documentation:

Now you will be thinking about, how to download SDK assemblies? And what about the nice SDK sample code that usually helps developers to get started, of course you can also reuse them in your implementation. Don’t worry you can still access Individual components and can download them separately from NuGet here

Also if you are working with Dynamics CRM since it’s early version, you will be aware of the complete metadata information for all the system entities that we used to get with SDK earlier. But it was not released after Dynamics CRM 2011 and we used to refer solution or metadata browser to get entities metadata information after that. But now there is a good news, we can again refer complete system entity as well as custom entities (Common entities used for solutions released by Microsoft like Field Service etc) metadata from here

So let’s get Started with Dynamics 365 Developers Guide !!