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<?php
/**
 * WooCommerce Extra Feature
 * --------------------------
 *
 * Make "state" field not required on checkout
 *
 */
 
add_filter( 'woocommerce_billing_fields', 'woo_filter_state_billing', 10, 1 );
add_filter( 'woocommerce_shipping_fields', 'woo_filter_state_shipping', 10, 1 );

function woo_filter_state_billing( $address_fields ) { 
  $address_fields['billing_state']['required'] = false;
	return $address_fields;
}

function woo_filter_state_shipping( $address_fields ) { 
	$address_fields['shipping_state']['required'] = false;
	return $address_fields;
}