So apart from Apple Music, what else can we expect this week?
As with last year's event, which saw the introduction of iOS 8, OS X Yosemite and new programming language Swift, we're unlikely to see any glitzy product launches. Instead, the spotlight will be squarely on system upgrades and new features, hopefully with the odd surprise thrown in. Here's everything we can expect from the year's most exciting developers conference.
"We've got incredible new technology for iOS and OS X to share with developers at WWDC and around the world, and can't wait to see the next generation of apps they create," said Apple senior vice president of worldwide marketing Phil Schiller.
An iPhone 6 running iOS 8 - what does iOS 9 hold?
iOS 8 was the undisputed star of WWDC 2015, and its a fairly safe bet to say we'll see the introduction of iOS 9 this time round. Key features are predicted to include Force Touch support, new kernel-level security system Rootless, which has been designed to put an end to jailbreaking iOS devices, and split-screen mode support to turn the iPad into a business-focused beast.
It's expected the first device to ship with iOS 9 will be the next generation of iPhones - likely to be called the iPhone 6s and 6s Plus - which are slated to go on sale in late September, if recent release cycles are to be believed.
Apple Pay: the death of the wallet?
While US customers have been able to use Apple Pay on their iPhone 6 and 6 Plus (and more recently, Apple Watch) since October last year, we in the UK have been left waiting. We should see an announcement declaring the contactless payment system is being rolled out to select parts of Europe and Canada, allowing UK shoppers to pay for goods and services using our phones as contactless devices.
Negotiations between Apple and UK banks over the introduction of Apple Pay to these shores have been fraught over the level of personal and financial information Apple wants to collect about its customers, sources told the Telegraph last year.
It's also believed a rewards scheme to incentivise customers to use Apple Pay could be rolled out at the event. Google used its I/O developers conference last week to launch Android Pay in the US, which also uses NFC technology and hopes to replicate the widespread early adoption rates Apple Pay has seen.
Is a new and improved Apple TV in the pipeline?
One of the strongest pervading rumours about WWDC this year is that we'll see a new fourth-generation Apple TV. Given that 2013 was the last time it was updating, a new offering is well overdue.
It's been reported for a while that the company is looking into launching an online TV streaming service in partnership with broadcasters including Fox, ABC and CBS via an online subscription costing from $30, which could stand to boost sales of Apple TV set top boxes.
Back in March Apple announced at the Apple Watch Spring Forward event that it had secured exclusive early access to the forthcoming HBO Now streaming service, allowing Apple device owners to watch popular series such as Game of Thrones.
Apple Watch: apps ahoy
With the Apple Watch comes a whole new app eco-system for developers to play with, and with this year's WWDC the first since its launch, the event is unlikely to go unmarked. The company is already catering for its Watch-wearing faithful, after updating its WWDC app with Apple Watch support in late May.
Apple's senior vice president of operations Jeff Williams revealed in an interview last week that a software development kit designed to create Watch-native apps would be released during WWDC, meaning third party apps won't need to bat back to the paired iPhone all the time, but run independently on the Watch itself.
The first Watch OS update 1.01 was issued in mid-May, offering improved Siri performance alongside third party apps and calorie calculation amendments. Due to this extremely recent roll-out, we probably won't be witness to any significant software rollouts.
A new typeface
A slightly more random announcement is the potential decision for Apple to replace favoured font Helvetica Neue across iOS 7 upwards and OS X Yosemite with a custom-designed San Francisco typeface. First debuted on the Apple Watch, San Francisco was designed "specifically for legibility", and scales more dynamically to “maintain clarity and legibility”, according to 9to5Mac.
First announced at WWDC 2014, HomeKit is a framework designed to house Internet of Things apps, such as Google-owned Nest's smart thermostats and wireless door locks, in a unified Siri-integrated dashboard through the Home app. The company has previously hinted that HomeKit accessories will make an appearance by June, but the app and framekit have yet to fully launch.
The latest version of OS X, believed to be codenamed Gala, is a safe bet. Like iOS, it's probable a short preview will be given during the keynote and it will be made available to download for free from October or so.
Like its predecessors Mavericks and Yosemite, the new software is likely to bear a California-related name, given that Apple has trademarked the use of location terms including Big Sur, Sequoia and Mojave.
Any updates are unlikely to be as dramatic as last year's Yosemite, which was a significant aesthetic departure from Mavericks. OS X 10.11 will probably place a greater focus on stability optimisation and improving performance overall.
And one more thing....Apple Car?
Okay, this is a massive long shot, but as reports Apple is developing a car gather credence, this year's keynote may extend beyond CarPlay. Jeff Williams recently admitted "Well the car is the ultimate mobile device, isn't it?", hinting heavily at the possibility we'll see a fully Apple-designed car in the future, but it almost definitely won't make an appearance next week. Given that Sir Jony Ive has been freed up of his day-to-day management responsibilities due to his recent promotion to chief design officer, maybe an automobile will become the new Apple of his eye?
Ever since Apple paid $3bn for Beats Electronics and online music streaming service Beats Music last May, music lovers, the Apple faithful and analysts alike have been waiting to witness the fruits of a partnership between the two American mega-brands.