How to update outdated Minecraft Mods?

Say I want to use a mod that's made for 1.7.2, but the current Minecraft version is 1.7.9. How could I make the mod work for 1.7.9? Is it possible to do so with a bit of editing in the coding?

It depends on the mod. Most mod authors do not like it when others port, edit, or copy mod information.

If the mod is simple and open sourced, You could talk to the developer about a port, otherwise there's nothing you could do except wait.