SIGNL4 comes with a very flexible scheme of detecting, mapping and displaying alert severity or criticality. As each 3rd system, e.g. IT monitoring tools, might have separate ways of tagging their event severity, we have implemented what we call 'alert categories'.
Using the categories, you can easily map event severity into SIGNL4 categories displaying the relevance of alerts. And you can even assign specific push sounds/ring tones to alert levels.
Here is a video on how it's done, in this sample with 3 different severity levels - critical, major and minor: