Z-Wave - Secure or not Secure

I have an issue with a couple of my switches. They often lose connection. I purchased a device that will work as Z-Wave repeater.

When I wanted to add this device to my HA, I found the following under the Add Node Secure section:

Note that unsecure devices can't directly talk to secure devices. 

I am not sure if the switches that have issues were added as secure or not secure node. How can I check?

Can I change the node status? Obviously, I want all of my devices to be either secure or not secure. I want them all to communicate directly. I am not sure if my older switches could be added as secure nodes.

Thank you.

It should only matter if you’re using Associations - which is (as far as I understand it) what that warning is about.