Just wondering is there any way to report on how many users are logging in via the Discourse app (rather than just logging in via browser)?
We are using Discourse’s own hosting on the Pro plan, in case that makes a difference.
Searched to see if this had come up before but didn’t find anything.
Hmm. 
I’m not 100% sure I’m right on this, but I don’t think there’s a record of that.
Unfortunately the Pro plan doesn’t include the data explorer plugin, which is the main way to create custom reports, so even if the data does exist you may be a little limited if there’s not an existing one included in the dashboard reports.
Though as a hosted customer you can also contact the support team directly at team@discourse.org (or send @team a message while logged in here on meta). Hopefully they’ll be able to give you a definitive answer. 
Thanks.
I will drop the team a message and report back here if it’s possible.