Update not working

In this case, I recommend upgrading manually: https://codex.wordpress.org/Upgrading_WordPress_Extended

Don’t worry, it’s not as difficult as it looks, the guide is just incredibly detailed.

That’s entirely possible.

Start with the update first, and if that doesn’t fix it, I recommend contacting them over at http://codecanyon.net/item/layerslider-responsive-wordpress-slider-plugin-/1362246/support