Date Module Cannot Be Disabled: (Field type(s) in use

I am also wondering how this should be handled. I can't just deleted the date field from all of my content.

Maybe I should look into using drush?

Same problem... Am I missing something obvious? I can't update the Date module because it cannot be disabled. The only dependency showing is a list of fields.

Same problem. Can't update from 7.x-2.6 to 7.x-2.8

I forgot about this question since it is over 2 years old. It's a newbie mistake so maybe this will help others that find this post.

To upgrade a module you don't need to disable it. Instead do this:

1) make a backup of the old date module and place that backup OUTSIDE of Drupal.
2) Delete the date module that is still inside of Drupal (By deleting the folder)
3) Copy in the new version of the date module (unzip the new version into your modules directory where the old folder was)
3) Go to your-drupal-site-here.com/update.php
4) This will advise you to backup code/database etc (I covered the code part in steps 1+2 above), it will check for updates, and then it will apply updates as needed. It should all go smoothly and the new version of the module will be properly installed.

ALWAYS run these steps on a staging/development server first just in case it doesn't go smoothly. It would be a real pain if it accidentally messed up your production website.

Hope that helps clear things up!

There used to be official instructions specifying that contrib. modules be disabled. But this seems to be obsolete now.
Lately, I use Drush which has greatly simplified the process even more.