Apple's CEO Tim Cook attends the Apple Worldwide Developers Conference (WWDC) 2015 in San Francisco, the United States, June 8, 2015. [Photo/IC]

Plenty of updates on Apple Inc's three software platforms – OS X, iOS and watchOS, have been unveiled at the firm's 26th annual Worldwide Developers Conference on Monday.

Kicking off the event at San Francisco's Moscone Center, CEO Tim Cook pointed out that WWDC is "the epicenter of change for not only Apple but the industry".

"WWDC will host 100 sessions this week, uniting developers from 70 countries with more than 1,000 Apple engineers," Cook said.

"Last year's updates on Apple's Mac OS and iOS are leap-forward improvements while this year’s changes are more detail-oriented updates," said Li Yan, a Chinese WWDC attendee, iOS app engineer of Shanghai Liulishuo Information Technology Ltd. The app provides online oral English teaching for Chinese.

According to Li, the new watch OS reveals what kind of services the Apple Watch will provide to its users that will differentiate it from iPhone.

Li also pointed out that the open source move by Apple's own programming language, Swift, is palatable and it will bring both challenges and opportunities for the language developers' community.

"We think Swift is the next big programming language, the one that we'll all be doing application and system programming on for 20 years to come," said Craig Federighi, Apple's senior vice president of Software Engineering. "We think Swift should be everywhere and used by everyone."

"The open source of Swift is a good move for Apple as more developers will contribute on the platform so as to boost the company's coding language," said Zhang Min, a Chinese iOS engineer who works for domestic photo application developer, meitu.com.

According to Zhang, by comparison with other open source coding platforms, the Apple Store, which have secured tremendous users and download volumes, provides a big business potential for developers and investors.

On Apple Music, Li Yan expressed a wait-and-see attitude by saying "the Apple Music is different from domestic online music services providers, such as xiami.com," and who is the new platform's target audience is a question that has to be asked.

"Apple Music reflects Apple's ambitions in developing a new eco-system for online music customers," said Cai Qi, senior UI designer works of meitu.com. "I've seen some gorgeous outlook in the app, such as the 'For You' section of Apple Music that provides personalized playlists for users."

Here are some of the highlights on Apple's latest software updates at the 2015 WWDC.

OS X El Capitan

"OS X delivers unparalleled integration between Mac hardware, iOS devices, apps and online services, and has helped Mac sales outpace the PC industry every year for the last decade," said Federighi.

"Customers loved last year's landmark OS X Yosemite release and made it the fastest-adopted PC operating system ever. With El Capitan, we're further refining the Mac experience with enhancements to window management, Spotlight and built-in apps, and improving performance so everyday activities -- from launching apps to accessing email -- are faster and more responsive."