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Every WP Engine site has revisions disabled in its wp-config.php file. When revisions are enabled, our team noticed that performance issues tended to crop up fairly often. Because of this, it is our recommendation to keep revisions disabled in order to assure optimal site performance.

It is still possible to enable revisions on your site by editing the line in wp-config.php where it says:

define('WP_POST_REVISIONS',FALSE);

If you make changes to the number of revisions that your site can save, please contact our support team so we can make sure our system does not automatically disable your changes.

The WordPress Codex features a solid article that covers the assorted customizations that one can make on revisions here:

http://codex.WordPress.org/Revision_Management

Note: We only recommend making customizations to your site’s wp-config.php file if you are knowledgeable enough to make PHP code changes. This type of customization is beyond our scope of support since we do not recommend making this change.