Dirsync, Azure AD Sync, Azure AD Connect, and now Azure AD Connect v2. The second version of Azure AD Connect is important because it’s not an automatic upgrade, and has some different requirements.
Microsoft’s documentation Introduction to Azure AD Connect V2.0 covers this off well, and you can do an in-place upgrade, but read that link first. Microsoft are recommending you upgrade to this now, as mentioned in the article.
If you’re not sure what version of Azure AD Connect you’re on, you can log onto your server running the agent, bring up apps and features, and select Microsoft Azure AD Connect. Here I’ve got v18.104.22.168:
You can download the latest version from https://www.microsoft.com/en-us/download/details.aspx?id=47594
You may find that TLS1.2 isn’t enabled on your server – for me, it wasn’t enabled by default on Windows Server 2019. The registry keys and PowerShell script to change them is available here: https://docs.microsoft.com/en-us/azure/active-directory/hybrid/reference-connect-tls-enforcement
If you try to install without doing this, you’ll have to exit, then run Azure AD Connect which will be ready to upgrade – don’t try to re-run the MSI you downloaded.
The upgrade itself is fairly unexciting, which is what we want when making changes in production that allow the entire organisation to authenticate:
You’ll need to use Azure AD Administrator credentials as a part of the install.
Once done, you can go back to Apps & features to see the new version:
Also it’s worth checking Synchronization Service Manager to make sure it’s syncing without error. All you need to do is open the program which is installed as a part of Azure AD Connect, and see the status and times. If there’s an error, it’ll tell you.
That’s it, you’ll be up and running on Azure AD Connect v2, with auto updates happening again to keep you continually updated.