On the My Systems page, there is a bell symbol on the right hand side of the page. Clicking that will open universal system alerts settings, which you can edit for email and push notifications.
You can also edit alert settings for each individual system by opening the system and clicking the bell in the right hand corner. This will open a similar settings box as seen in the first image.
You can also edit alerts for individual systems on your app. Select the PRO tab at the bottom of the page, then choose the SYSTEMS tab along the top. Click on a system to open its details. From there, click that same bell symbol on the right hand side of the page to edit your settings.