the 6th-generation iPod classic and 3rd-generation iPod nano. In conjunction with the iPhone 4 in 2010, Apple began using Helvetica Neue on devices with Retina display, while keeping use of Helvetica on non-Retina devices. Around 2012, Apple started using Helvetica in macOS (then named OS X) application software. iTunes, iMovie, iPhoto, GarageBand, and Apple's professional applications started to feature heavy use of Helvetica, while the majority of the OS X (now named macOS) environment retained the comparatively more legible Lucida Grande typeface, which was designed specifically for on-screen use. After the introduction of iOS 7 in June 2013, Apple began using an extra-thin weight of Helvetica Neue for the user interface of iOS 7, arousing numerous complaints about the less legible typography. For the final release of the operating system, Apple changed the system's font to a slightly thicker weight of Helvetica Neue, although some have complained that readability is still compromised compared to the font weight used in former versions of iOS. Older iOS devices continue to use Helvetica or Helvetica Neue in regular font weights that display with higher contrast on low-resolution displays. With the introduction of OS X 10.10 "Yosemite" in June 2014, Apple started using Helvetica Neue as the system font on the Mac. This brought all of Apple's user interfaces in line, using Helvetica Neue throughout. San Francisco San Francisco is currently used for user interface across all of Apple's product line, including watchOS, macOS, iOS, iPadOS and tvOS (with the notable exception of subtitles on tvOS which continues to use Helvetica). The three main variants are SF Pro for macOS, iOS, and iPadOS; SF Compact for watchOS; and SF Mono for the Terminal, Console, and Xcode applications. It was first introduced alongside the Apple Watch, where it was used for enhanced legibility and taller x-heights for easy reading on a small display. The design references a number of different other typefaces, notably FF DIN (used in the UI of the Camera app in iOS 7 and above), Helvetica (used in the UI in iOS 6 and below), Helvetica Neue (used in the UI of iOS 7 and iOS 8 as well as OS X Yosemite), Roboto (Google's new UI typeface), and Univers (used on Apple's early keyboard designs). It was widely speculated that San Francisco was going to be the long-awaited font that Apple had reportedly been developing for independent use in their products,