[andrewstuart]

>>You are free to compile and use custom kernels.

What's exactly does this mean? Could you please post the link to the documentation page that explains how?

[Tassels]

It's like on any Linux or BSD machine. You can build and install the kernel normally, and it just works.

Only some of the older images still use the old method of selecting the kernel from the Control Panel. The rest that Andrew mentioned use the bootloader and kernel from the droplet's image itself.