这里有一种更好、更自动化的方法（如下所示this 答案）：

class MyPlugin{

  const 
    OPTION_NAME = \'my_plugin_options\',
    VERSION     = \'1.0\';

  protected
    $options  = null,

    // default options and values go here
    $defaults = array(
                  \'version\'     => self::VERSION, // this one should not change
                  \'test_option\' => \'abc\',
                  \'another_one\' => 420, 
                );

  public function getOptions(){

    // already did the checks
    if(isset($this->options))
      return $this->options;    

    // first call, get the options
    $options = get_option(self::OPTION_NAME);

    // options exist
    if($options !== false){

      $new_version = version_compare($options[\'version\'], self::VERSION, \'!=\');
      $desync = array_diff_key($this->defaults, $options) !== array_diff_key($options, $this->defaults);

      // update options if version changed, or we have missing/extra (out of sync) option entries 
      if($new_version || $desync){

        $new_options = array();

        // check for new options and set defaults if necessary
        foreach($this->defaults as $option => $value)
          $new_options[$option] = isset($options[$option]) ? $options[$option] : $value;        

        // update version info
        $new_options[\'version\'] = self::VERSION;

        update_option(self::OPTION_NAME, $new_options);
        $this->options = $new_options;  

      // no update was required
      }else{
        $this->options = $options;     
      }


    // new install (plugin was just activated)
    }else{
      update_option(self::OPTION_NAME, $this->defaults);
      $this->options = $this->defaults; 
    }

    return $this->options; 

  }    

}

下面是我如何解决这个问题的总结。更新选项的触发器是检查是否存在新选项“版本”。从现在起，如果需要，我可以进行版本比较。

（我不确定回答我自己的问题是否正确，或者更新问题是否更好……）

class MyPlugin {
    var $adminOptionsName = "MyPlugin";

    function MyPlugin() {
    }

    function init() {
        $this->getAdminOptions();
    }

    function getAdminOptions() {

        // New options and values
        $theNewOptions = array(
            \'option_1\' => 0,
            \'option_2\' => \'\',
            \'version\'  => \'1.0\'
        );

        // Grab the options in the database
        $theOptions = get_option($this->adminOptionsName);

        // Check if options need update
        if( !isset($theOptions[\'version\']) && !empty($theOptions) ) {
            foreach( $theOptions as $key => $value ) {
                if( $key == \'not_needed\' ) {
                    unset( $theOptions[$key] );
                }
                if( $key == \'old_option_1\') {
                    $theOptions[\'option_1\'] = $value;
                    unset( $theOptions[$key] );
                }
                // etc...
            }
        }

        // Proceed to the normal Options check
        if (!empty($theOptions)) {
            foreach ($theOptions as $key => $option) {
                $theNewOptions[$key] = $option;
            }
        }

        update_option($this->adminOptionsName, $theNewOptions);

    }
}