Title: $callback as nullable is deprecated
Last modified: December 18, 2025

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# $callback as nullable is deprecated

 *  Resolved [Jakours2](https://wordpress.org/support/users/jakours2/)
 * (@jakours2)
 * [5 months, 3 weeks ago](https://wordpress.org/support/topic/callback-as-nullable-is-deprecated/)
 * Hello team!
 * I got this warning : FluentForm\Framework\Support\Collection::sort(): Implicitly
   marking parameter $callback as nullable is deprecated, the explicit nullable 
   type must be used instead in **/home/xyz/public_html/wp-content/plugins/fluentform/
   vendor/wpfluent/framework/src/WPFluent/Support/Collection.php** on line
   Could
   you help me?

Viewing 4 replies - 1 through 4 (of 4 total)

 *  Plugin Support [Amimul Ihsan](https://wordpress.org/support/users/amimulihsanmahdi/)
 * (@amimulihsanmahdi)
 * [5 months, 3 weeks ago](https://wordpress.org/support/topic/callback-as-nullable-is-deprecated/#post-18762151)
 * Hi there,
 * It seems like a PHP deprecation notice. It does not indicate a functional problem
   with FluentForms. It does not affect form submissions, payments, or data. Your
   site should continue to work normally. However, could you please let us know 
   which PHP version your site is currently running on?
 * Thank you
 *  [Zack Pyle](https://wordpress.org/support/users/zackpyle/)
 * (@zackpyle)
 * [2 months, 2 weeks ago](https://wordpress.org/support/topic/callback-as-nullable-is-deprecated/#post-18861753)
 * This is a PHP 8.4 notice: [https://php.watch/versions/8.4/implicitly-marking-parameter-type-nullable-deprecated](https://php.watch/versions/8.4/implicitly-marking-parameter-type-nullable-deprecated)
 *  Thread Starter [Jakours2](https://wordpress.org/support/users/jakours2/)
 * (@jakours2)
 * [2 months, 2 weeks ago](https://wordpress.org/support/topic/callback-as-nullable-is-deprecated/#post-18862367)
 * yep!
 * // before
   function foo(array $items = null) {}
 * // remplace by
   function foo(?array $items = null) {}
 *  Plugin Support [Rahul Das](https://wordpress.org/support/users/testerrahul/)
 * (@testerrahul)
 * [2 months, 2 weeks ago](https://wordpress.org/support/topic/callback-as-nullable-is-deprecated/#post-18863121)
 * Hello there,
 * Would you please check downgrade your PHP version to 8.3 or lower and check again?
 * Thank you

Viewing 4 replies - 1 through 4 (of 4 total)

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 * 4 replies
 * 4 participants
 * Last reply from: [Rahul Das](https://wordpress.org/support/users/testerrahul/)
 * Last activity: [2 months, 2 weeks ago](https://wordpress.org/support/topic/callback-as-nullable-is-deprecated/#post-18863121)
 * Status: resolved