I installed a couple of updates for SharePoint and tried to run the Config Wizard. Well, it didn't go so well, because some updates were missing on some servers, even after I installed them. I found this little PowerShell cmd: Get-SPProduct -local So, now: What does this do?
As far as I know, this will check the registry for required farm wide updates and also I think it is checking different MSI-Package Installation information. After that it will run a stored procedure on SQL Server which will update the product version. This might sound a bit sketchy, but if I find more detailed information out there I will link it below.
It is important to note that you can run this with "-local", to get only the information of the server you are on, but also without "-local" which will return the products installed on the farm.
Source: Technet
*edit*
As promised: I found more information on that command -> The Magic of Get-SPProduct -Local by Trevor Seward