One of the more annoying aspects of owning a smartphone on a not fully-updated version of Android can be emoji. Not how they look, but which ones your device supports. If you're running an older OS version, you probably don't have the latest Unicode revision of the emoji character library, and that can lead to the infamous blank square issue.
With Android O, Google is going to solve this problem, even if in a less-than-ideal way. The new emoji support library (EmojiCompat) will allow app developers to simply place said library in their application, at which point all emoji that the latest version of Android supports will be available to users of said app. Granted, the emoji that the device doesn't support would probably differ in appearance from any manufacturer-customized emoji on the device, which makes the experience less than ideal (presumably, standard Android emoji would be shown), but it's better than a blank square, right?
Because this is a support library, that does mean that apps will have to individually be updated to support this feature, which obviously isn't a guarantee of anything - some app developers may just choose not to care. But it's a problem that can be fairly annoying when you encounter it, so Google is at least doing something to remedy the issue.
Granted, it won't really make any difference for older devices now - just Android O and going forward.
The emoji support library is actually compatible all the way back to KitKat (API 19), which is awesome news - this means older devices do get support for this feature, as long as app developers use the EmojiCompat library in their apps. No more blank emoji!
- Android Developers