Fatal Error Ocean Popup Login with Php. 7.4

Hey,
when switching to Php 7.4 from 7.3 the Customizer doesn′t open anymore because of this error from the Ocean Popup Login Extension. Error Message below. What can I do to solve this problem?

Thanks
Jakob

Fatal error: Uncaught Error: Using $this when not in object context
in /is/htdocs/wp12665440_E3YPSSJKWG/www/wp-content/plugins/ocean-popup-login/ocean-popup-login.php on line 272

Call stack:

Ocean_Popup_Login::customizer_options()
wp-includes/class-wp-hook.php:287
WP_Hook::apply_filters()
wp-includes/class-wp-hook.php:311
WP_Hook::do_action()
wp-includes/plugin.php:478
do_action()
wp-includes/class-wp-customize-manager.php:933
WP_Customize_Manager::wp_loaded()
wp-includes/class-wp-hook.php:287
WP_Hook::apply_filters()
wp-includes/class-wp-hook.php:311
WP_Hook::do_action()
wp-includes/plugin.php:478
do_action()
wp-settings.php:568
require_once()
wp-config.php:70
require_once()
wp-load.php:37
require_once()
wp-admin/admin.php:34
require_once()
wp-admin/customize.php:13