Array value operators
array('value' &gt;= 4) is not the correct syntax to define an array containing the index value.

Basing on Fixed conditionals to allow OR and XOR constructions, you can use the following code.

$form['model'] = array(
  '#type' =&gt; 'select',
  '#title' =&gt; t('Select a Model'),
  '#options' =&gt; array(0 =&gt; t('- Select -')) + $options,
  '#default_value' =&gt; 0,
  '#states' =&gt; array(
    'visible' =&gt; array(
      array(
        array(':input[name=platform]' =&gt; array('value' =&gt; 4)),
        array(':input[name=platform]' =&gt; array('value' =&gt; 5)),
        array(':input[name=platform]' =&gt; array('value' =&gt; 6)),
        array(':input[name=platform]' =&gt; array('value' =&gt; 7)),
      ),
    ),
    'required' =&gt; array(
      array(
        array(':input[name=platform]' =&gt; array('value' =&gt; 4)),
        array(':input[name=platform]' =&gt; array('value' =&gt; 5)),
        array(':input[name=platform]' =&gt; array('value' =&gt; 6)),
        array(':input[name=platform]' =&gt; array('value' =&gt; 7)),
      ),
    ),
  ),
);


Using this code, the form field will be visible when the other form field value is one of the following values: 4, 5, 6, 7. It works with Drupal 7.14, or higher.