San Francisco (sans-serif typeface) and iOS 10 is a new variant named "SF Compact Rounded". It is used in the new contact placeholder icons introduced in the OSes. The "SF Serif" variant was showcased during the keynote at WWDC 2018 on June 4, 2018 when the all-new Apple Books app was introduced. This variant is exclusive to Apple Books in iOS 12 and macOS Mojave, is not mentioned in Apple's Typography design guidelines, and is not publicly downloadable like other variants of the San Francisco typeface. Since its introduction, San Francisco has gradually replaced most of Apple's other typefaces on their software and hardware
Helvetica as better than any previous digital release of Helvetica: Users include Bloomberg Businessweek and the Whitney Museum. It originated from an abandoned redesign plan for the "Guardian" newspaper. The release does not include condensed weights or Greek and Cyrillic support. As one of the most iconic typefaces of the twentieth century, derivative designs based on Helvetica were rapidly developed, taking advantage of the lack of copyright protection in the phototypesetting font market of the 1960s and 70s onwards. Some of these were straight clones, simply intended to be direct substitutes. Many of these are almost indistinguishable from Helvetica, while some