Yellow Square with Exclamation mark inside. Usually followed by a safety message. iEmoji old name: Caution.
Emoji History The emoji code/ image log of changes.
This emoji was part of the proprietary / non-standardized emoji set first introduced by Japanese carriers like Softbank. These emojis became part of the Apple iPhone starting in iOS 2.2 as an unlockable feature on handsets sold in English speaking countries.
In iOS 5 / OSX 10.7, the underlying code that the Apple OS generates for this emoji was changed.
The code generated for this emoji was changed slightly in iOS 7 / OSX 10.9 (a variation selector was added) advising the OS to display character emoji style instead of black and white text when available. We don't mind Apple, thank you! We just love our emojis! [Sources 11438-emoji-var.pdf 13.7 Variation Selectors (unicode.org)]