Upgrading your wordpress install is vital considering the updates generally contain important security patches.

You could follow the Wordpress guide here or the extended guide, and manually upgrade it risking accidentally deleting your theme file….

OR

You could install the automatic wordpress upgrade plugin and let it take care of everything for you, even creating the necessary backup files.

This plugin is likely the best thing that has ever happened to me.  I just used it a few days ago to update my install to the newest build.  Wonderful.