update NowPlayingCenterInfo for iOS 8.2 (even if you only wish to update the artwork).

updateNowPlayingCenter

- (void)updateNowPlayingCenter:(NSDictionary *)info
{
    if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"8.2") && SYSTEM_VERSION_LESS_THAN(@"8.3"))
    {
        NSString *zeroLengthString = @"\u200B";
        NSString *title = info[MPMediaItemPropertyTitle];
        NSString *currentTitle = [MPNowPlayingInfoCenter defaultCenter].nowPlayingInfo[MPMediaItemPropertyTitle];
        NSUInteger index = [currentTitle rangeOfString:zeroLengthString].location;
        if (index == NSNotFound)
        {
            info[MPMediaItemPropertyTitle] = [NSString stringWithFormat:@"%@%@",title,zeroLengthString];
        }
        else
        {
            info[MPMediaItemPropertyTitle] = title;
        }
    }
    [MPNowPlayingInfoCenter defaultCenter].nowPlayingInfo = info;
}

I've noticed that this works if I change the image once or twice, but after that it just stops updating it until something more drastic changes (eg playback rate). I've also got this issue that after I set the whatever changes to the nowPlayingInfo center, after about 500ms it'll reset everything to empty, and I'll have to re-apply the changes. What on earth, apple!