In Drupal, if several modules need updating, is it OK to copy all the files across and run update.php once, or do I need to copy each module individually and run the update each time? Thanks
From drupal.org: "The update script should only be run once. It will complete all the updates at once. If prompted for which version, choose the closest starting version that makes sense for you."
In general, you should be able to perform all of your updates at once. That said, if you have modules that have interdependencies and which don't take programmatic steps to ensure their dependencies are installed and up-to-date in your system, you could ostensibly experience an error in the update process by running them all at once.
So if you have "mainstream" modules, I wouldn't worry about anything; just upgrade all at once. If you have modules with several interdependencies that don't receive as much development attention, it would be a good idea to make sure you upgrade modules in a specific order to satisfy dependencies.