Mulitisite WPCF7 – PHP fatal error

I wanted to let you know I downgraded to version 6.1.2 to have the plugin working on multisite installation.

6.1.3 gave me PHP fatal error on all WPCF7 admin page with php8.1 and php8.3.8 at least :

[12-Nov-2025 09:14:22 UTC] PHP Warning:  Undefined array key "form" in /wp-content/plugins/contact-form-7/includes/formatting.php on line 376
[12-Nov-2025 09:14:22 UTC] PHP Warning:  Undefined array key "form" in /wp-content/plugins/contact-form-7/includes/formatting.php on line 379
[12-Nov-2025 09:14:22 UTC] PHP Fatal error:  Uncaught TypeError: array_merge(): Argument #1 must be of type array, null given in /wp-content/plugins/contact-form-7/admin/admin.php:562
Stack trace:
#0 /wp-content/plugins/contact-form-7/admin/admin.php(562): array_merge()
#1 /wp-includes/class-wp-hook.php(324): wpcf7_admin_integration_page()
#2 /wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters()
#3 /wp-includes/plugin.php(517): WP_Hook->do_action()
#4 /wp-admin/admin.php(260): do_action()
#5 {main}
  thrown in /wp-content/plugins/contact-form-7/admin/admin.php on line 562