IE9 Compatibility

Drupal 8.4 dropped support for IE 9 and 10, with workarounds to support them starting to be removed in 8.5. This module preserves those workarounds where possible to maintain compatibility with IE 9.

Other modules can also use this module to control their own IE9-specific behaviour:

  if (\Drupal::moduleHandler()->moduleExists('ie9')) {
    // Do IE9-compatible behaviour.
  }

Included Workarounds

• CSS Rendering no longer includes workaround for Internet Explorer 9
  Production sites should use CSS aggregation to reduce the number of included stylesheets so that this workaround is not needed.

Modules that integrate with IE9 Compatibility

• IE9 Compatibility alters Content-Security-Policy to add 'unsafe-inline' to the style-src directive when necessary.