Android – major version 51 is newer than 50, the highest major version supported by this compiler
By: Kevin | August 21, 2014
If you have ever seen this warning while trying to build an Android project and wasn’t sure what to do to fix it, let me save you some time.
“Major version” means Java version. Java 7 = 51 and Java 6 = 50. The code is written for Java 7, and that is something that Android’s dex supports.
The simple fix takes you into your project setting and change the version of Java you’re compiling against.
Of course you need to have Java 7 installed. If you don’t just do a quick google search and install and try the above again.