Apparently, Linus Torvalds is not quite ready to move the Linux kernel to version 5; the next release will be 4.17, and he expects to go up to 4.20. None of that is of great importance, but some features in the new 4.17 kernel are. (You can read about them here (https://itsfoss.com/linux-kernel-4-17/). Of particular interest is that it will incorporate some power savings features that could help laptop users get more out of their batteries. It will also incorporate drivers for new AMD GPU's.
I do wonder whether the kernel will just be incorporating energy savings that I get anyway with TLP, or if this is something additive.