How to check for version of app and request users to update?

Question

How can I check if the user has the current version of my app and also pop up a message to request them to update their app version?

Something like what you would see below.

Answer 1

You need to have a WebService on your server (or something similar) that your app requests at startup, to know which is the latest version available. (If you don't have a WS yet and really don't want to implement one for that, you may also simply use an XML or text file that contains the version too)

Then compare this version retrieved from your server with the current version of the application, using [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"].

If they are different, you can display the alertview and redirect to itms-apps://phobos.apple.com/WebObjects/MZStore.woa/wa/viewSoftwareUpdate?id=[APPID]&mt=8 (replacing APPID with your iTunes Connect App ID), which is the link that will make your iPhone open the AppStore application directly on your application's update page

Answer 2

To check to see if you have the latest version just query iTunes for app data using the following query (note: change the id to match your app's id from iTunesConnect):

http://itunes.apple.com/lookup?id=520604518

This returns a JSON dictionary which is very easy to convert to an NSDictionary to use directly within your code, then all you need to do is pull out the value for the "version" key and compare it against your apps version number (see version key/value bolded below):

{
    "resultCount": 1,
    "results": [
        {
            "kind": "software",
            "features": [],
            "supportedDevices": [
                "all"
            ],
            "isGameCenterEnabled": false,
            "artistViewUrl": "https://itunes.apple.com/us/artist/d-m-holdings/id388608883?uo=4",
            "artworkUrl60": "http://a899.phobos.apple.com/us/r1000/086/Purple/v4/6d/b3/05/6db305aa-c685-558b-8c8e-8b7245375ce1/IconAudio.png",
            "screenshotUrls": [
                "http://a86.phobos.apple.com/us/r1000/078/Purple/v4/8f/ff/47/8fff4783-f2e4-fe3f-ef92-96d67d66c12b/mzl.dwbdvxny.png",
                "http://a731.phobos.apple.com/us/r1000/097/Purple/v4/cb/65/f6/cb65f613-408a-dffe-fb36-165db0c1a360/mzl.jexyhdnq.png",
                "http://a940.phobos.apple.com/us/r1000/097/Purple/v4/f6/26/a1/f626a18c-691f-7345-8d3d-f19713144818/mzl.llsgsagl.png",
                "http://a185.phobos.apple.com/us/r1000/071/Purple/v4/7d/5e/bc/7d5ebcad-7755-e772-727c-65de99effd60/mzl.zuyvhebk.png",
                "http://a48.phobos.apple.com/us/r1000/096/Purple/v4/d6/f5/f1/d6f5f108-10ab-3738-26cf-5ce82c6bb690/mzl.ijtyynie.png"
            ],
            "ipadScreenshotUrls": [],
            "artworkUrl512": "http://a672.phobos.apple.com/us/r1000/100/Purple/v4/e3/cb/5d/e3cb5d2d-f1a8-8b80-3a91-58be8f654710/mzm.uogqezwx.png",
            "artistId": 388608883,
            "artistName": "D&M Holdings",
            "price": 0,
            **"version": "1.0.5",**
            "description": "Designed to enhance the listening experience with Denon’s new line of Music Maniac™ headphones, the Denon Audio app is designed for the on-the-go audiophile. The Denon Audio app features a premium audio player that lets you experience the best possible sound quality from your iPod music library and favorite Internet radio stations. Create & save custom EQ curves, create & save instant playlists, enjoy internet radio stations via the built-in TuneIn service, and more. The Denon Audio app will quickly replace all of your other music apps.\n \nThe Denon Audio app features a customizable graphical equalizer that lets you contour your own sound by directly manipulating more than 1000 discrete bands of equalization without adding spatial distortion or decreasing sound quality. Pump up the bass, restore those highs, and start jammin’! \n \nEQ FEATURES:\n \n• Graphical equalizer for your iPod music library and streaming Internet Radio\n• 1000 possible discrete bands\n• 10 built in EQ Presets\n• Create and save your own EQ Presets\n• Bypass mode to quickly compare the original and equalized audio\n• Real-time spectrum analyzer\n• Linear phase design\n• No spatial distortion\n\nIPOD MUSIC LIBRARY FEATURES:\n\n• Enhances your listening experience with Denon Music Maniac Headphones or other audio playback devices such as docking stations, a/v receivers, car stereos via USB, Bluetooth, or Airplay.\n• Powerful queue based playback system lets you build and order your own playlist on the fly.\n• Save the playback queue as a new playlist\n• A single song, all songs on an album, all songs by an artist, and all songs in a genre can easily be added to the now playing queue.\n• Supports both portrait and landscape modes for browsing, playing, and equalizing\n• Shuffle and repeat playback modes\n• iPod library browsing by Playlist, Artist, Album, Song, Genre, Composer, Compilation, and Podcast (no importing needed)\n\nINTERNET RADIO FEATURES:\n\n• The TuneIn service provides global access to Internet radio – covering over 70,000 radio stations and 2 million on-demand programs including sports, news, talk, music and comedy. \n• Browse Internet radio stations by location, genre, language or Podcast (on-demand programs).\n• Powerful search feature for your iPod music library and Internet Radio \n• Save your favorite Internet Radio stations or programs as convenient presets and share them with  other TuneIn compatible devices\n• Ability to choose high or low quality streams offered by broadcasters\n \nADDITIONAL FEATURES:\n\n• Streams music over AirPlay to any Denon AirPlay compatible receiver or HiFi product\n• Share what you’re listening to via Facebook, Twitter, Email, or Text Message (iMessage)\n\nNOTICES:\n \n• The Denon Audio app requires iOS 5 or later and works with the iPhone 3GS or newer, the iTouch 3rd generation or newer, and all iPads (in 2x mode). \n• DRM protected iTunes music is NOT supported by the Denon Audio app (or any 3rd party music app)\n• iTunes Match will be supported in a future update \n• WiFi or data connection required to stream Internet radio",
            "currency": "USD",
            "genres": [
                "Music",
                "Lifestyle"
            ],
            "genreIds": [
                "6011",
                "6012"
            ],
            "releaseDate": "2012-05-29T07:00:00Z",
            "sellerName": "D&M Holdings Inc.",
            "bundleId": "com.dm-holdings.denon-audio",
            "trackId": 520604518,
            "trackName": "Denon Audio",
            "primaryGenreName": "Music",
            "primaryGenreId": 6011,
            "releaseNotes": "• Added 4\" display support for the iPhone 5 and 5th generation iPod Touch\n\n• Added an audio limiter function to protect against possible distortion introduced from pushing the EQ too high\n\n• Displays the Shuffle, Repeat, AirPlay, and Share icons as well as the scan/scrub controls on the \"Now Playing\" screen by default (so everyone knows they are included in the app). Tap the cover art to hide/show these controls",
            "formattedPrice": "Free",
            "wrapperType": "software",
            "trackCensoredName": "Denon Audio",
            "trackViewUrl": "https://itunes.apple.com/us/app/denon-audio/id520604518?mt=8&uo=4",
            "contentAdvisoryRating": "4+",
            "artworkUrl100": "http://a672.phobos.apple.com/us/r1000/100/Purple/v4/e3/cb/5d/e3cb5d2d-f1a8-8b80-3a91-58be8f654710/mzm.uogqezwx.png",
            "languageCodesISO2A": [
                "ZH",
                "DE",
                "EN",
                "ES",
                "FR",
                "JA",
                "NL"
            ],
            "fileSizeBytes": "9060882",
            "sellerUrl": "http://www.usa.denon.com/headphones",
            "averageUserRatingForCurrentVersion": 4.5,
            "userRatingCountForCurrentVersion": 329,
            "trackContentRating": "4+",
            "averageUserRating": 4.5,
            "userRatingCount": 471
        }
    ]
}

Here is some code to accomplish this task. -rrh

NSURL *url = [[NSURL alloc] initWithString:[NSString stringWithFormat:@"http://itunes.apple.com/lookup?id=%@",APPSTORE_ID]];
NSURLRequest *request = [NSURLRequest requestWithURL:url];

[NSURLConnection sendAsynchronousRequest:request
                                   queue:[NSOperationQueue mainQueue]
                       completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
                           if (!error) {
                               NSError* parseError;
                               NSDictionary *appMetadataDictionary = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:&parseError];
                               NSArray *resultsArray = (appMetadataDictionary)?[appMetadataDictionary objectForKey:@"results"]:nil;
                               NSDictionary *resultsDic = [resultsArray firstObject];
                               if (resultsDic) {
                                   // compare version with your apps local version
                                   NSString *iTunesVersion = [resultsDic objectForKey:@"version"];

                                   NSString *appVersion = [[[NSBundle mainBundle] infoDictionary] objectForKey:(NSString*)@"CFBundleShortVersionString"];
                                   if (iTunesVersion && [appVersion compare:iTunesVersion] != NSOrderedSame) { // new version exists
                                       // inform user new version exists, give option that links to the app store to update your app - see AliSoftware's answer for the app update link
                                       UIAlertView *alert = [UIAlertView bk_showAlertViewWithTitle:APP_NAME message:[NSString stringWithFormat:@"New version %@ available. Update required.",iTunesVersion] cancelButtonTitle:@"update" otherButtonTitles:nil handler:^(UIAlertView *alertView, NSInteger buttonIndex) {


                                        NSString *iTunesLink = [NSString stringWithFormat:@"itms://itunes.apple.com/us/app/apple-store/id%@?mt=8",APPSTORE_ID];
                                        [[UIApplication sharedApplication] openURL:[NSURL URLWithString:iTunesLink]];
                                       }];
                                       [alert show];
                                   }
                               }
                           } else {
                               // error occurred with http(s) request
                               NSLog(@"error occurred communicating with iTunes");
                           }
                       }];