Class file has wrong version 52.0, should be 50.0

Question

I\'m trying to compile my project in IntelliJ idea. I\'m using a class in an external jar file and on compilation receiving the above error.

I understand that it\'s

Answer 1

Have got the same error as in header because of failed attempt to compile my project with java 8 and then reattempting to compile with java 6. Some classes where compiled at the first attempt with 8 and did not recompile with 6. Mixed classes did not compile then. Cleaning project solved the problem. This answer is not strictly relevant to the question, but could be useful for someone.