Wp-super-cache: Missing mod_expires

Hi gurus,

I recently upgraded my wp-super-cache plugin to the latest version.

Upon installation however, it says:

The following Apache modules are missing. The plugin will work without them but your visitors may see corrupted pages or out of date content.

* mod_expires – Set the expiry date on supercached pages. Visitors may not see new pages when they refresh or leave comments without this module.

My rod rewrite rules seem to be correct:

WP Super Cache mod rewrite rules were detected in your /home/xxx/domains/mrdefinite.com/public_html/.htaccess file. Click the following link to see the lines added to that file. If you have upgraded the plugin make sure these rules match. View mod_rewrite rules

I have also added rules to /home/xxx/domains/mrdefinite.com/public_html/wp-content/cache/.htaccess

Can you please tell me what I am missing? My website is at https://www.mrdefinite.com.

Your help is very much appreciated.

Regards,
Kenneth Lee