Multiple Notice Errors

Hello, even though I have warnings turned off. I continue to get multiple Undefined Indexes throughout your code. Can you please adjust these ASAP. They cause issues, and I need to always adjust them myself.

This is just one of them. But please find the issue and fix.

Notice: Undefined index: wh_popups_change_wh_to in //wp-content/plugins/warehouse-popups-woocommerce/public/class-warehouse-popups-woocommerce-public.php on line 858