Title: WordPress 4.9 compatibility
Last modified: January 23, 2023

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# WordPress 4.9 compatibility

 *  [Viktor Nagornyy](https://wordpress.org/support/users/viktorix/)
 * (@viktorix)
 * [3 years, 4 months ago](https://wordpress.org/support/topic/wordpress-4-9-compatibility/)
 * Plugin claims to be compatible with WordPress 4.7, but it looks like you’re using
   functions from WordPress 5+ and it throws an error in WordPress 4.9. This also
   makes the plugin incompatible with ClassicPress.
 * Specifically `wp_is_json_request` and `wp_timezone_string`.
 * You can test it using [WPSeek’s Plugin Doctor](https://wpseek.com/pluginfilecheck/).
 * I would recommend either bumping the minimum required version or using `function_exists`
   to check if those functions exist to continue to be compatible with WordPress
   4.7 or 4.9 (and ClassicPress for that matter).

The topic ‘WordPress 4.9 compatibility’ is closed to new replies.

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 * 0 replies
 * 1 participant
 * Last reply from: [Viktor Nagornyy](https://wordpress.org/support/users/viktorix/)
 * Last activity: [3 years, 4 months ago](https://wordpress.org/support/topic/wordpress-4-9-compatibility/)
 * Status: not resolved