How to get Agenda app for Mac OS 10.11

I have and old Macbook running on OS 10.11, which I use sometimes. I wanted to find if I can get the agenda app for this verison somehow, so that I can keep my notes synchronised. Please advise.

I’m sorry, we aren’t able to do that. We released the first version on macOS 10.12. It would be a lot of work to make it also work on the older OSes. Sorry.