The issue with the App requiring later updates on iPhones that no longer support IOS updates has not gone away. Our I phone 7 which is perfectly good won't support IOS 16.0 or later so no App, and we are not buying a new phone just for that!!
Unfortunately, this is the way tech works these days; planned obsolescence. You could upgrade to to a used, "newer" phone that supports iOS 16.0 and higher (no need to buy a very expensive, latest model phone), or switch to just using a desktop computer only. Unfortunately, most don't carry a laptop around with them and rely on their phones for access to Airbnb via the App.
If you start google chrome on your iPhone 7, you should be able to go over to airbnb.ca and log in, and should be able to see the top 3 messages at least.
I have similar issues with an iphone 8 which is still on ios 14.5.1 by choice.
Thanks guys for the responses. I think that Air BnB needs to have a moment of reflection. Every time they create a (mostly unnecessary) new version of the App, they need to ask “how many members will we be alienating by doing this?”. None of course if we all use the web - but that goes against the direction of travel and is less convenient - but no one can convince me that they aren’t able to keep older supported versions going. After all, these are smart people - who simply lack a rear view mirror.