One of the most requested features since My Artists launched in August has been a track scrubber.
My Artists 1.1.3 replaces the slider previously used to change volume with a control to monitor and adjust the current playback position.

OBSlider
I started with a standard UISlider with custom graphics. I quickly realised that, like in the iPod app, when trying to seek to a particular second within a track we need to have finer control over the position of the slider-thumb than a standard UISlider offers.
Luckily, Ole Begemann has just produced OBSlider (blog post | source on github), “a drop-in replacement for UISlider with the addition of variable scrubbing speeds.” By simply dropping in Ole’s class and adjusting a few variables to optimise scrubbing speed I had a slider that offered the fine control I needed. While dragging the slider-thumb into position the user can adjust scrubbing speed, just like in the iPod app, by sliding their finger vertically away from the control. Sliding back towards the control adjust scrubbing speed back to normal and brings the slider-thumb back into line with your finger.
MPVolumeView with AirPlay
The volume control, which now also supports AirPlay source selection, is now revealed along with the artist biography by tapping on the artist photo. This is opposite to where the iPod app positions the controls but makes more sense to me since most iOS devices now have physical volume control buttons, thus making the on-screen controls less important.

Developers are somewhat limited in how they can add an AirPlay route selector to their apps. At the moment the only supported way is to add an MPVolumeView, which contains a system volume slider and, if available, an AirPlay route selector button.
The volume slider can be disabled by setting the showsVolumeSlider property to NO and then you would have a control that just shows an Airplay button when multiple routes are available but there is no way, yet, to programatically tell whether multiple routes have been detected or not and dynamically update the interface yourself to accommodate the additional button, as the iPod app does. There is also no way to customise the appearance or size of the button which is a pity because the 18 point high tappable area is frustratingly easy to miss with your finger.
Appirater
Not a feature per se but another addition to My Artists with 1.1.3 will be presenting itself to regular users of the app in a few days time.
To encourage positive app store reviews and ratings I wanted to add a timely alert to My Artists 1.1.3 that would politely ask users of the app to rate the latest version.
A quick search uncovered Appirator (blog post | source on github) by Arash Payan, a very useful class that takes care of tracking how long a user has had the latest version of your app installed, how many times they’ve used it, and how many times they’ve performed any particular “significant event”. Once your desired conditions have been met the user will be presented with an alert view asking if they would consider rating your app.

Once the Appirator class has been added to your project you set certain constants like your App ID and the conditions that should be met before the user is asked to rate the app. In My Artists’ case, users of a particular version must have it installed for 3 days, have used the app at least 10 times, and have loaded the Now Playing screen at least 10 times.
You then make calls to the following class methods from the relevant places within your code:
+ (void)appLaunched:(BOOL)canPromptForRating;
+ (void)appEnteredForeground:(BOOL)canPromptForRating;
+ (void)userDidSignificantEvent:(BOOL)canPromptForRating;
This made it exceptionally easy to set up My Artists so that only those who regularly use the app (hopefully, by extension, those who like it the most) are prompted to rate it in the App Store and ensure that they are prompted at a fairly opportune moment (the Now Playing screen most often loads when the user has made a music choice and the music has just begun playing).