New features

- Drupal 9 readiness changes

This is the first release of Metatag that is compatible with Drupal 9, thanks to several wonderful people who spent time debugging issues and rewriting parts of the module.

It should be noted that this release is compatible with Drupal 8.7.7+, 8.8, 8.9 and 9.0. There are some test regressions for 8.7 due to compatibility problems with the Page Manager and Redirect modules. It is no longer compatible with 8.7.6 or any release of 8.6.

Added styling library for the new static map options for paragraph type simple map.

Changes
- Refactors to use classes instead of callbacks for providers
- Improves documentation on extending and altering

Adds
- Base class for providers
- Pop up class for providers
- Common interface for extending

Removes
- Callback function usage

• Fixed JS coding standards
• Improved performance by introducing Advagg and optimizing CSS
• Fixed update process
• Fixed validator errors
• Fixed accesibility issues
• Added lazy loading of images
• Fixed minor bugs