Contiguous simply means touching or sharing a border, according to Merriam-Webster. When it comes to the United States, contiguous refers to all of the states that touch one another, without another country or a body of water coming between them. These are sometimes also referred to as the lower 48 states.
.apk extension stands for android package file. It is a file format used to distribute and install applications.It includes the programm codes ,assets ,resourses ,certificates and manifest file. .Dex extensions stands for Dalvix Executable files.
The APK is signed by Google and installs on top of your existing Play Store. It's safe to install if you'd rather have the latest version without having to wait for Google to randomly push it to your device. Download and install it just like any other APK. 1  Android Police mirror #1.