I've inherited control of a website running Drupal v7.4 and noticed right away that it wants to be upgraded to v7.23. This seems like a pretty extreme upgrade, skipping over 19 intervening versions of Drupal. Is this even possible to do in one step? Or do I need to do it one version at a time (which seems like it would take hours)? I've never attempted an upgrade that was more than one version number more advanced, so any advice on this would be helpful. Thanks!