Microsoft Defender that you get by default on Windows is an unmanaged solution. It detects, but it is conventional EDR in the sense that it can detect malicious code on the machine, but it is not good from an enterprise point of view because you can't see what is being detected. The difference between Defender and Defender ATP is that you get what's called the execution chain, which is its classic use case.
When I try to open an attachment to an email, Defender tells me that this is malicious, but when you are in an enterprise and you do receive an alert that the file is malicious, the problem usually for the analyst is that they don't know what the person clicked on. They know there was a malicious file but was it an attachment? Was it something on the USB stick? Did they download it from the internet? That's not clear. Defender ATP gives you the execution chain. In this particular example, you can see that it was outlook.exe that launched the suspicious file which then launched or tried to download various components. You can see the whole execution tree because very often, the initial thing you get is a dropper, which then downloads subsequent components, and very often, the subsequent components get missed.
It essentially gives you visibility into the execution chain. So, you are better able to do a risk assessment. For instance, if something came from Outlook, then you know that you need to go and look in exchange or look in the mail system. If the trigger came from winword.exe, then you know that it was a document, and the person had opened a document from the email. You might see Internet Explorer, when it was still there, spawn PowerShell or a command shell, which is unusual, or you might see calc.exe open a command shell. All of this detection is invaluable for identifying whether something is suspicious or not. Your EDR might not detect any of this, but ATP would see this suspicious sequence of opening and flag it. So, essentially it is the visibility and the ability to detect unusual behavior that conventional EDR would not necessarily do for you.
Its version is usually up to date. It is a cloud solution.