Title: Fatal error on plugin activation
Last modified: September 16, 2020

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# Fatal error on plugin activation

 *  Resolved [jonejr](https://wordpress.org/support/users/jonejr/)
 * (@jonejr)
 * [5 years, 10 months ago](https://wordpress.org/support/topic/fatal-error-on-plugin-activation-32/)
 * Hi
 * After the plugin activation, I got a fatal error in WP.
 * I am not a developer, so could you please give me some clue about it?
 * Thanks.
 * Fatal error: Uncaught Error: Call to undefined function acf_version_compare()
   
   in /XXXX/wp-content/plugins/acf-extended/init.php on line 55
 * Call stack:
 *  acfe_plugin_row()
    wp-includes/class-wp-hook.php:287 WP_Hook::apply_filters()
   wp-includes/class-wp-hook.php:311 WP_Hook::do_action() wp-includes/plugin.php:
   478 do_action() wp-admin/includes/class-wp-plugins-list-table.php:1220 WP_Plugins_List_Table::
   single_row() wp-admin/includes/class-wp-plugins-list-table.php:698 WP_Plugins_List_Table::
   display_rows() wp-admin/includes/class-wp-list-table.php:1322 WP_List_Table::
   display_rows_or_placeholder() wp-admin/includes/class-wp-list-table.php:1249 
   WP_List_Table::display() wp-admin/plugins.php:764

Viewing 3 replies - 1 through 3 (of 3 total)

 *  Plugin Author [Konrad Chmielewski](https://wordpress.org/support/users/hwk-fr/)
 * (@hwk-fr)
 * [5 years, 10 months ago](https://wordpress.org/support/topic/fatal-error-on-plugin-activation-32/#post-13414588)
 * Hello,
 * Thanks for the feedback. Can please provide the following information:
    - Your WordPress version
    - Your ACF Pro version
 * ACF Extended requires ACF Pro 5.8 (at least), and the error you get says that
   the `acf_version_compare()` function doesn’t exists (which exists in ACF Pro 
   5.8).
 * This error should not be thrown if you try to load an older version of ACF pro,
   as there are some checks that occur before, which is really weird.
 * Regards.
 *  Thread Starter [jonejr](https://wordpress.org/support/users/jonejr/)
 * (@jonejr)
 * [5 years, 10 months ago](https://wordpress.org/support/topic/fatal-error-on-plugin-activation-32/#post-13414677)
 * Hi. Thanks for the feedback.
 * Just got ACF updated. It works now.
 * Thank you anyway.
 *  Plugin Author [Konrad Chmielewski](https://wordpress.org/support/users/hwk-fr/)
 * (@hwk-fr)
 * [5 years, 10 months ago](https://wordpress.org/support/topic/fatal-error-on-plugin-activation-32/#post-13414849)
 * Hello,
 * Okay I found where the problem come from. This PHP error shouldn’t occur, there
   will be a clean warning message when users don’t have ACF or an old ACF version.
   Thanks for your report 🙂
 * This will be fixed in the next version.
 * Sorry for the inconvenience.
 * Regards.

Viewing 3 replies - 1 through 3 (of 3 total)

The topic ‘Fatal error on plugin activation’ is closed to new replies.

 * ![](https://ps.w.org/acf-extended/assets/icon-256x256.png?rev=2071550)
 * [Advanced Custom Fields: Extended](https://wordpress.org/plugins/acf-extended/)
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 * 3 replies
 * 2 participants
 * Last reply from: [Konrad Chmielewski](https://wordpress.org/support/users/hwk-fr/)
 * Last activity: [5 years, 10 months ago](https://wordpress.org/support/topic/fatal-error-on-plugin-activation-32/#post-13414849)
 * Status: resolved