You will need to install a user script manager extension to install this script.
Detector installation status for scripts on Violentmonkey.
This is a userscript to work with Violentmonkey 2.6.4+.
It changes the label of install button on userscript sites according to version of currently installed script, i.e. if there is an update, the label may be something like
Upgrade to v2.x.x.