You need at least Lightroom 5.2 to have support for that camera. You can purchase an upgrade from Adobe for $79.
Thanks I thought so - I know this is probably a dumb question but I should buy Lightroom 5, and then get the downloads to 5.2 free from adobe, is that right. Or do a buy 5.2 Lightroom?
Once you buy LR 5 you can install any of the LR 5.x versions where LR 5.7 just came out and supports the newest cameras, like the Nikon D750 or Canon 7D Mark II along with all earlier models.
It would be wise to download and install the LR 5.7 as a trial and make sure it works for you before buying the upgrade. The minimum OS is 10.7 and Win 7, I think, so if you’re on XP or Vista or OS X 10.6 then you’re out of luck.
The various version of LR are available on the Adobe Updates site: http://www.adobe.com/downloads/updates/
They will run in trial mode for 30 days or until you enter appropriate serial numbers.