Title: Multisite error update
Last modified: September 17, 2025

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# Multisite error update

 *  Resolved [Quique5](https://wordpress.org/support/users/quique5/)
 * (@quique5)
 * [8 months, 4 weeks ago](https://wordpress.org/support/topic/multisite-error-update/)
 * version 6.15.2 is working fine in MultiSite installations but I cannot upgrade
   now. I get a error for functions duplicates in ms.php:
 * After update to 6.15.4 I get this:
 * _`PHP Fatal error: Cannot redeclare check\_upload\_size() (previously declared
   in /home/www/multisite/htdocs/wp-admin/includes/ms.php:20) in /home/www/multisite/
   htdocs/wp-admin/includes/ms.php on line 20, referer: https://*****`_
 * Thanks in advance
    -  This topic was modified 8 months, 4 weeks ago by [Quique5](https://wordpress.org/support/users/quique5/).

Viewing 2 replies - 1 through 2 (of 2 total)

 *  Plugin Support [Darian](https://wordpress.org/support/users/d0153/)
 * (@d0153)
 * [8 months, 4 weeks ago](https://wordpress.org/support/topic/multisite-error-update/#post-18645639)
 * Hi [@quique5](https://wordpress.org/support/users/quique5/)
 * Thank you for reaching out!
 * After reviewing, I can confirm that our plugin does not declare the function 
   check_upload_size(). This issue is likely originating from your WordPress core
   files. I recommend updating your WordPress installation to the latest version
   to see if that resolves the problem.
 * As always, please make sure to test any updates on a staging site before applying
   changes to your live website.
 * If you have any further questions or need additional assistance, please let me
   know—I’m here to help!
 *  Plugin Support [Darian](https://wordpress.org/support/users/d0153/)
 * (@d0153)
 * [8 months, 3 weeks ago](https://wordpress.org/support/topic/multisite-error-update/#post-18648573)
 * Hi there,
 * Since there hasn’t been any recent activity on this thread, I’ll go ahead and
   close it for now. If you run into any other questions or need a hand, please 
   don’t hesitate to reopen this thread or open a new one.

Viewing 2 replies - 1 through 2 (of 2 total)

The topic ‘Multisite error update’ is closed to new replies.

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 * 2 replies
 * 2 participants
 * Last reply from: [Darian](https://wordpress.org/support/users/d0153/)
 * Last activity: [8 months, 3 weeks ago](https://wordpress.org/support/topic/multisite-error-update/#post-18648573)
 * Status: resolved