Upgrading pureOS

I am not exactly sure how to frame my question so bear with me. I installed pureOS a month ago and have been using it on and off but for the last week I have been using it exclusively. I am a new linux user so it is a bit uphill at times. This morning I wanted to install ring.cx and I think I need the package for debian based distros. Available here https://ring.cx/en/download/gnu-linux

This version is for Debian 9 and I am having an issue installing it, I tried a few different things but ultimately I think I need a version of libva1 that I don’t have

The following packages have unmet dependencies:
ring-daemon : Depends: libva1 (>= 1.7.3) but 1.4.1-1 is to be installed

I found elsewhere the version of libva1 I need is available in Debian 9. So here are a couple of my questions

What version of Debian is pureOS currently running?
How are updates/upgrades to Debian (Jessie to Stretch, I believe they are called) occur?
When pureOS downloads and install software updates do these also update Debian from 8 to 9?

Thank you,

PureOS is based on Debian „Buster“ (current testing), other info here: https://puri.sm/posts/what-is-pureos-and-how-is-it-built/

Ring website offers binary package for Debian 9, you need the package for Debian 10.

Solution: install ring from PureOS repos.

Thank you. Like I said I am new to linux so bear with me still.

When I go to the software app to install ring I get the same error that the package have unmet dependencies.

If pureOS is Debian buster, do I need to add entries for stretch and buster in the Software & Updates screen, as I currently only have entries for jessie in there?

Thanks again,

OK I got this to work. While looking in the Software & Updates screen I found an entry for the ring app for debian_9. This must have gotten added when I tried to install Ring through the terminal.

I unchecked and installed once again from software and it worked great.

Should I uncheck the entry for debian jessie as well in the Other software tab to avoid that any package that should come from the Pureos repo are installed from debian 8 repos?

Thank you

Yes, mixing repos is NOT good idea.