You won't have to wait until Apple's big iPad event to find out when iOS 12.1 will arrive. Apple has confirmed that the update will be available on October 30th (the day of the event) for all existing iOS 12-compatible devices. For most, the highlight will be the delayed Group FaceTime feature -- up to 32 people can chat at once, complete with a system that surfaces video based on who's speaking. You'll also be happy if you're an emoji fan, since Apple is adding more than 70 characters that include more hairstyles, animals and food.
The 12.1 upgrade will be particularly important if you're an iPhone XS, XS Max or XR owner. The new software enables dual SIM support using both the conventional SIM card slot and an eSIM. You'll need an eSIM-friendly carrier for this to work, of course, but it'll be helpful if you travel abroad or have separate work and personal lines. Also, you can now control the depth of field effect on portraits before you take a photo -- no more editing after the fact. And yes, this should address complaints that newer iPhones were inadvertently smoothing out face details in selfies.
Apple hasn't said exactly when the update goes live, but it typically releases updates around 1 PM ET.