Error if on PHP 7 server

Hi,
we are running Version 1.16.7

When we set wp_debug to “true” in wp-config and run your plugin with php 7.2,

We get the following error message at the backend and frontend:

Deprecated: Function create_function() is deprecated in /mysite.com/wp-content/plugins/onesignal-free-web-push-notifications/onesignal-widget.php on line 46

Deprecated: The each() function is deprecated. This message will be suppressed on further calls in /mysite.com/wp-content/plugins/onesignal-free-web-push-notifications/onesignal-settings.php on line 122

Could you please let us know how we can fix this error?