You found the simple notification extension, which only works for older devices
This is a simple notification extension and currently only runs on older Android versions, i.e. < Android 8.
Are you sure you like to use that extension?
The recommended extension to use is
What about dowloading it from there?
Taifun
PS: I now removed the simple notification extension from my website to help those, who are in a hurry and do not read the documentation