iOS 9.3 Update
iOS 9.3 add new features to your iOS device and is not just a run-of-the-mill maintenance update. New in iOS 9.3 is the ability to password protect individual Notes and Night Shift.
Password protection of the Notes app is nice feature especially if you often keep private thoughts mixed in with notes about buying eggs, milk, and bread at the grocery store. Personally, I don't often use the Notes app other than to jot down information quickly that I'll come back to later on and organize. Still, it is a nice feature to have available.
Night Shift is a very nice enhancement because it can use either the schedule you set or the sun down and sun rise information based on where you are in the world, to adjust the colors of your screen. Under normal conditions, your iPhone, iPad and iPod touch display emits a more harsh blue hue light. During the day, this does not create any problems. At night, however, exposing yourself to harsh blue light can make it harder for your to fall asleep if you use your iDevice just before bed. Night Shift will shift the color tones from the "cold" blue light to "warmer" yellow/orange light that is less likely to disrupt your body's natural processes for falling asleep. As you can see below, I have configured my iPhone 6s Plus to activate Night Shift based on the time of day. Night Shift, however, will only work on the iPhone 5s and later, iPad Pro, iPad Air and later, the iPad mini 2 and later, and the most recent iPod touch.
iOS 9.3 is available now for any iOS device that is capable of running iOS 9, which is pretty much any iOS device that has been released since 2011. The software and be installed from a Mac or Windows PC, or over the air using Settings > General > Software Update.
For more information on the new features of iOS 9, including those added with the iOS 9.3 update, visit the iOS 9.3 update website.
watchOS 2.2 Update
watchOS 2.2 is primarily as maintenance release for Apple's iPhone accessory. I'm not sure who needs to be able to pair more than one Watch with an iPhone, aside from app developers maybe, so I'm having a hard time coming up with who else might need this feature. (Are day and night watches really a thing?) I'm all for updates to the Maps app. The data behind Maps has gotten pretty good and any improvement that keeps from having to pull out my iPhone while trying to walk around Manhattan is a welcomed update for me.
To update to watchOS 2.2, launch the Watch app on your iPhone and goto General > Software Update. Before you can apply the update, your Apple Watch will need to be charged up to at least 50% and be in range of your iPhone, which, will wireless deploy the update to your Watch.