regions[content] is Required

I ran into an issue today. I rethemed a site in my development queue and declared my main content region as "regions[main_content]." This change introduced a problem that wasn't immediately apparent since the theme was already enabled on my development site.

However, when a colleague tried to rebuild this site minus the database, the Appearance page said "This version is not compatible with Drupal 7.x and should be replaced." Turns out that "regions[content]" is a required field for the theme .info file. Good to know.

You can read more here: http://drupal.org/node/785714