Most folks will suggest using AutoPkg and/or AutoPkgr running on a separate box, possibly paired up with a Jenkins server to automate the checking process. AutoPkg checks by themselves are not automated. They need to be invoked to go check for an updated version of software, but when its coupled with Jenkins, it can be more automated. Or, look at AutoPkgr, which also does this in a more automated way.
OTOH, there are certainly some scripted methods that can accomplish something similar. I have a script I created that can do on the fly version checking on a client and compare it to the latest release of a product and download the update and install it directly from the vendor if needed. I haven't published the newer version of my script yet because I still need to get around to working out a few kinks. But it can check against around 14 different apps/plug-ins for updates in one shot and download/install any that are needed.
