I’m not affected by the issue (maybe next year for my old iPhone) and I suspect the banner will perhaps go away after a set time, but I agree why not have a close option and maybe a ‘never show me this again’ check box, or something along those lines. A mobile screen is cluttered enough anyway these days and there’s no need for this banner to persist any longer than necessary.

Thanks Ken, I do hope it disappears as it’s highly distracting (for me at least). 

Yes my old iPad mini had that only used it as a media controller but switched to a full sized iPad without the warning shame no way to remove the warning

Betting it's permanent until you are using a device with supported iOS versions 

Of course it’s perfect on other devices, just not the iPhone which I use in the evenings to control Sonos. iPad goes on charge overnight whilst the iPhone goes upstairs.