Update URLS button throws error

Hi there,

like your plugin very much. Unfortunately, after Migration from Test to Live Server, the URLs of the Slides are still the Test URLs.

When I click the Button in the Help and Support Menu, I get

Fatal error: Uncaught Error: [] operator not supported for strings in /wp-content/plugins/ultimate-responsive-image-slider/help-and-support.php:65 Stack trace: #0 /wp-content/plugins/ultimate-responsive-image-slider/ultimate-responsive-image-slider.php(586): require_once() #1 /wp-includes/class-wp-hook.php(286): RIS_Help_and_Support_page(”) #2 /wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(”, Array) #3 /wp-includes/plugin.php(453): WP_Hook->do_action(Array) #4 /wp-admin/admin.php(224): do_action(‘ris_gallery_pag…’) #5 /wp-admin/edit.php(10): require_once(‘/…’) #6 {main} thrown in /wp-content/plugins/ultimate-responsive-image-slider/help-and-support.php on line 65

What can be done?

Thanks!