Can I force an iPhone user to upgrade an application?

        In general forcing the user to update our application mandatorily might not go well from user stand point.

        In-spite of the above fact,  Sometime you do have to force an Upgrade for security or other valid reasons. Lot of gaming applications in the market does this sought of updates.

        some of the Financial Enterprise apps which are right there in the App-Store were able to force app users to mandatorily update it to latest version.

How do i do this?

Get Version info Using Itunes web service 

NSURL *url = [NSURL URLWithString:@"http://itunes.apple.com/lookup?id=<Your app ID>"];

versionRequest = [ASIFormDataRequest requestWithURL:url];

versionRequest setRequestMethod:@"GET"]; 

versionRequest setDelegate:self];

versionRequest setTimeOutSeconds:100];

[versionRequest addRequestHeader:@"Content-Type" value:@"application/json"]; 

[versionRequest startSynchronous];

Response string of our REST call 

NSString* jsonResponseString = [versionRequest responseString];

NSDictionary *loginAuthenticationResponse = [jsonResponseString objectFromJSONString];

NSArray *configData = [loginAuthenticationResponse valueForKey:@"results"];

for (id config in configData)

{

    version = [config valueForKey:@"version"];

    

}

Compare Both Versions 

NSString *version = @"1.0";

if (![version isEqualToString:[itsUserDefaults objectForKey:@"version"]]) 

{

    UIAlertView *createUserResponseAlert = [[UIAlertView alloc] initWithTitle:@"New Version!!" message: @"A new version of app is available to download" delegate:self cancelButtonTitle:nil otherButtonTitles: @”Update", nil];

    [createUserResponseAlert show]; 

    [createUserResponseAlert release];//Avoid if using Automatic reference counting

}

Redirect User

-(void)alertView:(UIAlertView *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex

{

    NSString *iTunesLink = @"itms-apps://phobos.apple.com/WebObjects/MZStore.woa/wa/viewSoftwareUpdate?id=<appid>&mt=8";

    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:iTunesLink]];

}