Hello. Welcome to Android Central.
It is a name given to Android 4.4 (4.4.2 + 4.4.4) a recent major update to Google's operating system for most, although many devices have been upgraded to the next version - Lollipop / Android 5.0 and what fun that is! Before KitKat there were versions of Jelly Bean / 4.1. Some older devices will not be upgraded to the next operating system, sent over the air or pc, usually beyond 2 years.
The wait after a new version is announced and it is installed can vary enormously by device, region and especially carriers / networks as they have to test it and integrate it with their own device software.
If you are on Jelly Bean I would be happy with that, I liked it. An update can bring a lot of temporary problems.
You can go to Settings - About Device - Software Update to check if there is an update available. The About Device screen will also show which version you are currently on. I am on 4.4.2.
http://www.android.com/history/
Facebook
Twitter
Instagram