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iosnsurlsessionhttp2

HTTP/2 support for iOS 8

I tried Xcode 7 Beta + NSURLSession, which already supports HTTP/2 and it works just amazing.

Now I'm wondering, when I release the app built with iOS 9 SDK but with iOS 8 support - will iOS 8 users be able to use HTTP2 ? Or it will only work for iOS 9 ?

Solution

  • I asked the same question on the Apple Developers Forum and they gave a crystal clear answer:

    The HTTP/2 support is part of iOS 9, and thus won't be available on earlier OS releases.

    https://forums.developer.apple.com/message/31667

    But what is bothering me is iOS 8 behaviour. I'm still confused by your actual issue. I suspect you're talking about this case:

    1. you build an app using NSURLSession
    2. you deploy a server that supports HTTP/2
    3. on iOS 9, this will talk to your server via HTTP/2
    4. on iOS 8, this will talk to your server via HTTP/1.1 or SPDY
    5. on iOS 7, this will talk to your server via HTTP/1.1

    Whether this works really depends on your server. Ignoring iOS 8 and SPDY for the moment, consider the iOS 7 case. Here iOS is simply going to open the connection and send an HTTP command. What does your server do in that case? It should handle it correctly, but iOS can't guarantee that.

    OTOH, if I read your original question literally, you seem to be asking about this case:

    1. you build an app using NSURLSession
    2. you deploy a server that supports HTTP/2
    3. on iOS 9, this will talk to your server via HTTP/2
    4. on iOS 8, will it send HTTP/2 requests?

    The answer here is no: the HTTP/2 support is part of iOS 9, and thus won't be available on earlier OS releases. OTOH, iOS 8 does have support for SPDY. See WWDC 2014 Session 707 What's New in Foundation Networking for details.