The Apple Watch has attracted many wearable lovers but not many users know the significance and differences between the round and square notification icons in the Apple smartwatch. Here is why Apple has used two notification icon shapes in the Apple Watch.

Publication Mac Kung Fu explains the significance of round and square notifications. The round notification on the Apple Watch takes action on from the Apple Watch itself. However, a square notification needs the user to take action on their paired iPhone.

Users may query why Mail notifications appear in square shape and sometimes in round shape.

"If the notification is square then the message is not in your inbox - or not in the mailbox that you configured in the iPhone's Watch app for notifications. All you'll be able to do is dismiss this notification," clarifies Mac Kung Fu. "If the notification is round then, yes, it's in the inbox or designated mailbox. You'll be able to reply to it from the notification, and flag it, and so on."

This design feature of the WatchOS may have gone unnoticed by most of the users. Apple has cleverly designed the notifications icons but the company never highlighted the significance of the icon shapes.

Apple unveiled its first wearable - the Apple Watch - in September 2014 and the smartwatch hit the shelves in April 2015. The design of the Apple Watch has been applauded by experts and it is one of the most wanted wearables by iPhone owners.

According to an International Data Corporation (IDC) report, Apple shipped 3.6 million Apple Watches in Q2 of 2015 and occupied the second position in the wearable market. Fitbit was in the first position with total worldwide sales of 4.4 million units.

IDC also highlights that the total wearable shipment in the quarter was 18.1 million units, which is up by 223.2 percent in comparison to 5.6 million units shipped in the same quarter of 2014.

"Anytime Apple enters a new market, not only does it draw attention to itself, but to the market as a whole," says Ramon Llamas, Research Manager for IDC's Wearables team. "Its participation benefits multiple players and platforms within the wearables ecosystem, and ultimately drives total volumes higher."

Jitesh Ubrani, a senior research analyst at IDC, noted that two in every three smart wearables shipped in Q2 of 2015 was an Apple Watch. Apple should be praised as the company released its Apple Watch just a few months ago and the wearable was able to grab a major chunk of the market share.