Exactly the same problem as mine! Hopefully a fix very soon.
attempted to update to 3.56
received this error
Fatal error: Uncaught Error: Call to undefined function opcache_reset() in /home/omgc/www/www/wordpress/wp-content/plugins/nextgen-gallery/src/Util/Installer.php:124 Stack trace: #0 /home/omgc/www/www/wordpress/wp-content/plugins/nextgen-gallery/nggallery.php(844): Imagely\NGG\Util\Installer::update() #1 /home/omgc/www/www/wordpress/wp-includes/class-wp-hook.php(292): C_NextGEN_Bootstrap->update(”) #2 /home/omgc/www/www/wordpress/wp-includes/class-wp-hook.php(316): WP_Hook->apply_filters(NULL, Array) #3 /home/omgc/www/www/wordpress/wp-includes/plugin.php(484): WP_Hook->do_action(Array) #4 /home/omgc/www/www/wordpress/wp-settings.php(560): do_action(‘init’) #5 /home/omgc/www/www/wordpress/wp-config.php(75): require_once(‘/home/omgc/www/…’) #6 /home/omgc/www/www/wordpress/wp-load.php(37): require_once(‘/home/omgc/www/…’) #7 /home/omgc/www/www/wordpress/wp-admin/admin.php(34): require_once(‘/home/omgc/www/…’) #8 /home/omgc/www/www/wordpress/wp-admin/index.php(10): require_once(‘/home/omgc/www/…’) #9 {main} thrown in /home/omgc/www/www/wordpress/wp-content/plugins/nextgen-gallery/src/Util/Installer.php on line 124
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Now I cannot view the photos in any albums on my website.
Please fix or go back to v 3.55
Ver 3.57 fixed the URL issue.
Thanks