Kaseya Network Monitor has a function that checks for new versions on regular basis. Every 8 hours, counting from when the service was last started, KNM will check the URL http://download.kaseya.com/components/knm/v126.96.36.199/update.xml if there's a build that is newer than the current one. To be able to do so, the machine where the KNM server is installed would of course need access to the Internet. If your KNM host machine needs a proxy to connect, you can set a proxy with in KNM at K menu -> Other system settings -> Other settings. Under "Misc network settings", you can set a proxy server address and port.
Even if an automatic check is performed every 8 hours, you can still force an update check. Go to K menu -> Tools -> System administrator console and issue the command version -check
Now if you click on the K menu, you will see in the bottom right corner a notification about a new version with a link to the "Check for new version" page that you can also find in the K menu under "System settings."
At the version information page, you will find various links, and among them you will find a link to the latest build on Kaseya's download server. You will also find a link to the release notes regarding this specific build so you can check what changes that has been made.