Windows server 2016 .net framework

I have multiple servers running Windows Server 2016. For some reason some of them have .net 4.7.2 and some have 4.7.3. When doing some research 4.7.3 I do not see even see anyway. For some reason my application does not work with 4.7.2 but it works for 4.7.3. There has been no .net framework installed manually. Also all of the windows machines are up to date.

What would cause these to have different frameworks? Is there a version of .net 4.7.3?
Any assistance would be helpful.

Source: Windows Questions