There is an update of the latest stable version of Linux kernel 4.5.3 available in Sparky “unstable” repository.

To install or upgrade it, activate Sparky “unstable” repository:
https://sparkylinux.org/wiki/doku.php/repository
and install the latest kernel via the meta packages.
amd64:
sudo apt-get install linux-image-sparky-amd64
686 non-pae:
sudo apt-get install linux-image-sparky-686
686-pae:
sudo apt-get install linux-image-sparky-686-pae

Then reboot you machine to take effects.

To quick remove older version of the Linux kernel, simply run APTus-> Remove-> Uninstall Old Kernel script.