Mine did that for awhile. I uninstalled it and installed the latest version.
The latest versio 1.1.98. If it keeps asking you to upgrade, just reboot your computer and that should stop.
It doesn't stop if you reboot your machine. There is also a bug where v0.9 of Mavlink will be used instead of v1.0 of Mavlink after upgrading if the shortcut is pointing at the wrong software name. I'm going to do a fresh install, which should properly solve both issues.