iPhone is still going strong, having remained one of the most popular phones in the world – easily in the top ten globally – ever since the release of the first model, way back in 2007. As of right now, having an iPhone is a must and you can even buy a second-hand model – just make sure that you will unlock the iCloud account of the previous user (for more info, check Why the Lucky Stiff's tips for unlocking iCloud account). With such a broad customer base, it will come as no surprise that app developers are constantly inventing and innovating, coming up with new and exciting offerings to intrigue and tempt customers. Here are a few of our favourites for 2017:1. MessengerFacebook's messaging service has been grown up and left home, becoming a stand-alone app that can be downloaded by itself, without the need to go through Facebook. With Messenger you can message friends and family: and even make calls and chat using your mobile data so that no other charges are incurred. You can even include as many of your friends in a conversation thread as you'd like, so that you can stay in touch with the whole office, class or hobby group at once, enjoying camaraderie and making plans effortlessly. Messenger is free from the Apple Store.2. SignalIf you are security minded and value your privacy, why not invest in Signal, a communication app that keeps you protected with end-to-end encryption even as you make calls, send texts and otherwise stay in touch with your contacts. In order for the app to work, all parties must have the app installed. Signal is free from the Apple Store.3. Wolfram-AlphaTaking a page from many science fiction books and films, Wolfram-Alpha aims to be more than a search engine, rather, it aims to be a computational knowledge engine. This means that any enquiry fed into the search bar will come back with complete answers, rather than a list of results which the searcher has to further narrow down in order to arrive at the answer they seek. Search queries which are ambiguous will prompt Wolfram-Alpha to offer several refining choices to aid the program in arriving at the correct response. The program may offer similar topics or related themes as additional search parameters too. The answer format is a series of facts and informational nuggets which can be expanded by hovering the mouse's cursor over each item. Wolfram-Alpha costs US$2.29, while Wolfram-Alpha Pro is currently available for US$4.99 (with a discount for students).4. SwiftKey KeyboardThis offering from Touch Type is the answer to all those embarrassing and cringeworthy autocorrect fails that are a minor plague to modern living. SwiftKey saves you clicking away to type out lengthy messages by offering personalised predictive text that learns from you. Not only does the app learn your favoured words and phrasing sequences, but it can even understand words from a finger dragged over the relevant letters, adding spaces as needed, and even recognising the need for an emoticon where relevant. SwiftKey Keyboard is free from the Apple Store, but there are some in-app purchases that customers might want to invest in.5. Device 6A blend of detective fiction, suspense and gameplay, Device 6 leads the player mainly through a text-driven narrative. The player reads through and makes choices, following clues and hints to solve the mystery, with fresh information being released as progress is made through the game. Perhaps a better way to describe the game is as an interactive novel: no matter the description it promises to be an absorbing and fascinating game – one that will leave you wanting more. Device 6 costs £2.99 from the Apple Store.