As announced as part of the Azure AD Connect Version Release History page and shared here earlier, yesterday marked the end of Azure AD Connect version 18.104.22.168 and older versions of Azure AD Connect. This way, Microsoft starts enforcing its 18-month support policy for Azure AD Connect versions.
For Azure AD Connect admins, running an older version of Azure AD Connect has the following consequences:
Automatic Upgrades are disabled
As Microsoft ends support, Azure AD Connect becomes unsupported. Azure AD Connect does not support Automatic Upgrades in unsupported conditions.
Whereas previously, running Azure AD Connect with a Microsoft SQL Server (cluster) back-end was the most important reason for Azure AD Connect not to automatically upgrade, with Microsoft's new support policy, the reasons why the Automatic Upgrade feature stops increase.
Although not documented, the Automatic Upgrade feature has in recent months stopped working on Windows Server 2008 and Windows Server 2008 R2 installations and on Windows Server installations with out-of-date .NET Framework versions.
Upgrades my break
To go from older Azure AD Connect versions to newer Azure AD Connect versions, you can still perform manual upgrades. Just like new installs, upgrades may break at any point, because new versions are no longer tested on these platforms.
However, you can always use the Release Management process for Azure AD Connect to get to a supported state.
Running Azure AD Connect version 22.214.171.124 and older versions of Azure AD Connect doesn’t get you into trouble just yet, but you want to make sure you leave these versions sooner than later to avoid complications.