Incompatible device

Hello, my wifes Samsung Tab 4 has been running 16.1 for a long time and she said it wasnt updated to the new version so I took a look and when i went into the google market it said my I had a incompatible device. The version its running is 4.4.2 and its a Samsung SM-T537A. Can I just side load it from the website and if so which android version would I try X86? Thanks!