Starting from the release 1.16a there is a new feature that can be used in the home page.
On the left of each irrigation line name there is a check sign, if you click on the sign it will be changed to "x" and the water line will be deactivated immediately. If the watering line was running, it will be stopped and the line will be inactive until the flag is changed.
Well, this is not a stupid question at all.
Right now there is no update procedure, so you need to reinstall all over again.
There is a way to retain the configuration but it is not guaranteed to work especially if you have a quite old version.
The procedure:
1) Go to "Settings" page, scroll down and click the "DownloadConfigFile", a link to a .zip file will appear. Click on the link with right button and "save the link as" in one folder of your PC.
2) Install the new version of the system. You can check the version number in the about page.
3) Go to "Settings", scroll down on the "System Configuration Upload" section and click "choose file". Select the file you have previously saved and click "upload and apply". This will bring all the setting back (hopefully).
If you try it, let me know the results.
Cheers,
Angelo