If you are a creative cloud member install LR CC 2015, else you need to upgrade to LR 6, as it has camera raw 9.1 which is required for processing Nikon d7200 raw images.
You need LR6 or LR CC
You can buy from the following link. After clicking "Buy" change from Full to Upgrade; then select your existing LR product from the drop-down menu and the correct pricing will be displayed. Then simply choose “Add to Cart”
Or you can take a 30 day free trial via the Creative Cloud to test what’s new (some new features are only available to CC subscribers) and after the trial it’s possible to convert the CC version to the LR6 stand-alone version, upon purchase of a serial number and without any further installation. In either case make sure your computer meets the minimum system requirements.
Minimum system requirements
Another option would be to download the free DNG Converter, either version 9.1 or 9.1.1
and convert your NEFs to DNGs that can be opened and edited in LR5.