If you're talking about mobile applications, there are no official ones. You can access the forum via a browser the same way as you would from a computer/laptop though.
Bitcointalk works best already in any mobile browser so I don't think an app is necessary. Btw, there is no app but it is compatible to any devices.
One definitely cannot access bitcointalk on mobile the same way he does on a computer. And it's definitely not compatible with all devices
Bitcointalk is definitely not suited for any mobile browser, either on iOS or Android. Definitely not the same experience on mobile in terms of ease of use.
Why think of the IOS version of Bitcointalk.
Open your native browser or any browser of your choice then access bitcointalk.org there.
This forum is light so even with an average connection, loading time is fast.
The issue isn't loading times.
I share OP's concerns, I hope the new forum is mobile friendly. OP, I guess we'll just have to wait