I'm using the following meta tag to show a smart banner on the iOS safari browser to open and install the app, copied from apple guide to smartbanners:
<meta name="apple-itunes-app" content="app-id=6444793650">
this works for every app, except ours! the app id is:6444793650
I guess since the app is fresh, apple's lazy crawlers couldn't find time to crawl it!