[Private iOS API] Launch another application: http://swiftiostutorials.com/jailbreak-development-launch-another-application/

AppBackgroundUtil.m

// We need only one method, no need to import all the framework headers
@interface PrivateApi_LSApplicationWorkspace
- (bool)openApplicationWithBundleID:(id)arg1;
@end

@implementation AppBackgroundUtil

+ (void)bringOtherAppToFront
{
    PrivateApi_LSApplicationWorkspace* _workspace;
    _workspace = [NSClassFromString(@"LSApplicationWorkspace") new];

    // If the application is running in background, this will bring it to front. 
    // If the application is not running, it will launch it.
    [_workspace openApplicationWithBundleID:@"com.yourcompany.example"];
}

@end