Error notice is generated, when “force_postalcode” is missing from settings arra

Error notice is generated, when “force_postalcode” is missing from settings array.

Notice: Undefined index: force_postalcode in /wp-content/plugins/wp-store-locator/frontend/class-frontend.php on line 1802

on line 1802 in /frontend/class-frontend.php

    if ( $wpsl_settings['force_postalcode'] ) {
                    $geocode_components['postalCode'] = '';
                }

should be changed to

if ( isset( $wpsl_settings['force_postalcode'] ) && ! empty( 
    $wpsl_settings['force_postalcode']  ) ) {
    $geocode_components['postalCode'] = '';
}