For the last few years, owners of iPhone have been using the Helvetica Neue font to send messages and notes. But that may soon change, as iPhone users will be using a new font called San Francisco, which was created by Apple for the Apple Watch, with the switch expected to be confirmed at Apple's developer conference in June.

The original Helvetica font was designed in the 1950s and Neue Helvetica, which arrived in 1983, is a reworking of that design. Apple has been using Helvetica Neue as its system-wide font across all its mobile devices since releasing iOS 7 in 2013. The company began using the font in Mac computers after releasing the OS X Yosemite last year. Despite looking good in print, Helvetica Neue is not suitable for use in small size digital screens, as it lacks all the characteristics required for readability at small sizes or long passages, such as rhythm, openness, moderate letter spacing and contrast.

On the other hand, the Apple-created font San Francisco has rounded features and space between the letters that allows them to be pushed together without being bunched up, and doing away with the need for overly thin lines. Apple had designed San Francisco to be "highly legible" on smaller screens and the same font is currently being used in the Apple Watch. Apple also uses San Francisco in the keyboard of its new 12-inch MacBook.

Apple is now aiming to improve the readability of text on tiny screens or when users are quickly glancing at their device by using its new San Francisco font in the next versions of its mobile and desktop operating systems. Apart from improving readability, using the font in its upcoming operating system refreshes will also lend a consistent look to Apple's latest products. Apple's new font change is expected to arrive when users upgrade to OS X 10.11 on desktops and iOS 9 on iPhones.