Errata

Code example to convert an object to a usable NSData says:

NSData* object storedData = [NSKeyedArchiver ...

when it should say:

NSData* storedData = [NSKeyedArchiver ...

In the step, "1. Add constraints to the table view" the last sentence says, "To pin the position, select the small dotted red spacers for the Top and Left distance positions and leave the default values" when it should say "Top, Left and Right distance positions."
There should also be an additional sentence that says, "Then press the `Add Constraints` button."

Example of registering for a notification is missing "name:". It says:

[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(applicationEnteredBackground:)
UIApplicationDidEnterBackgroundNotification object:nil];

But should say:

[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(applicationEnteredBackground:)
name:UIApplicationDidEnterBackgroundNotification
object:nil];

The code to check the loaded objects is missing the and operator. It says:

if ([anArray isKindOfClass:[NSArray class]] [anArray count] >= 1) {
// we know it's an array, and has at least 1 object in it
}

but should say:

if ([anArray isKindOfClass:[NSArray class]] && 1 <= [anArray count]) {
// we know it's an array, and has at least 1 object in it
}

The third button is supposed to be a NSPushButton, no? Otherwise the reader ought be be informed to remove the image from the button or a but + sign will be visible on top of the "Publish" string.

The text says one should pin the table only to the Left and Top, while you also need to check Right in order for the table to resize according to the window.

Text says you should click "Attributes inspector" while in fact you should click "Size inspector" to be able to "[S]et the Relation to Greater Than or Equal."

I believe the last line of the code block at the top of the page is missing an ampersand. "error:error];" should be "error:&error];".