PowerEdge 1900 is very old server model and it does not have any automatic update options. If you have a supported operating system as per below link you can try Server Update Utility which is available in below link.  [URL] 
Hi all, I have recently got a Poweredge 1900 Tower that I am messing with and rebuilding personally. I am trying to see if there's a way in a Windows environment to automatically update drivers and firmware, instead of having to manually download updates? I am new to this side of things and am looking for hints and tips on how to do this.  Thanks!
Poweredge 1900 - ways to automatic update?