Thank you for quickly addressing this.
I installed version 1.6.1 but the activation still fails:
Fatal error: Uncaught Error: Class ‘Inactive__ConcurrentLogins_functions’ not found in /wpcom-124817830/wp-content/plugins/inactive-logout/src/inactive-logout-main.php:69 Stack trace: #0 /wordpress/core/4.8.1/wp-includes/class-wp-hook.php(298): Inactive__Logout_Main::ina_activate(”) #1 /wordpress/core/4.8.1/wp-includes/class-wp-hook.php(323): WP_Hook->apply_filters(”, Array) #2 /wordpress/core/4.8.1/wp-includes/plugin.php(453): WP_Hook->do_action(Array) #3 /wordpress/core/4.8.1/wp-admin/plugins.php(166): do_action(‘activate_inacti…’) #4 {main} thrown in /wpcom-124817830/wp-content/plugins/inactive-logout/src/inactive-logout-main.php on line 69
