If you're referring to the internal screen resolution being 1366X768 max, you likely have an HD screen, which is not capable of more than that.  Go into setup (F2 at powerup) and look for the screen information.  If it shows HD, that's all the screen is capable of.  If you need more, assuming one is available for your model, you need to replace the screen with an FHD panel. We don't know what your TV is, so check its manual for its capability.    
Expert advice needed - please! The max resolution I can set on my Latitude E7470 is 1366x768, no greater resolutions are offered.. I'm using the latest driver Version: Intel HD Graphics 520. I also checked with the Dell driver pages, & the driver is up to date. In Device Manager I ran 'Update Driver' & MS said it was up to date! I want to use the laptop to connect to my TV via HDMI, but 1366 x 768 is useless. I would greatly appreciate any advice.Thanks for any advice, and kind regards, Niloc1017-----------------------------------------------Latitude E7470, manf 2016, Intel i5, W10 Pro, 256GB SSD M.2 2280, 128GB SD card for portable apps etc, 8 GB ram----------------------------------------------
Expert advice needed - please!