我们将Drupal的某些Theme从Drupal 6复制到Drupal 7的时候，激活的时候可能会遇到这样的错误信息：
This version is not compatible with Drupal 7.x and should be replaced.
.info文件大致类似于这样：
name = theme1 description = 1st test theme core = 7.x engine = phptemplate stylesheets[all][]= style.css regions[left] = Left Sidebar regions[right] = Right Sidebar regions[featured] = Featured regions[content] = Content regions[header] = Header regions[footer] = Footer scripts[] = effects.js
.info看起来一切正常，专门查了Drupal Theme的手册，最后还是在 http://drupal.org/node/785714 找到了答案。
D7中下面这一行是必需的（也就是content区块必要的）：
regions[content] = 'content' ;; All D7 themes need this.