Fatal error after working fine for over a year

I am getting this error after using this plugin just fine for over a year. Help?

Fatal error: Uncaught Error: [] operator not supported for strings in /home/username/public_html/wp-content/plugins/woocommerce-table-rates/includes/class.tablerate.php:188 Stack trace: #0 /home/username/public_html/wp-content/plugins/woocommerce/includes/abstracts/abstract-wc-shipping-method.php(207): rp_tablerates->calculate_shipping(Array) #1 /home/username/public_html/wp-content/plugins/woocommerce/includes/class-wc-shipping.php(333): WC_Shipping_Method->get_rates_for_package(Array) #2 /home/username/public_html/wp-content/plugins/woocommerce/includes/class-wc-shipping.php(260): WC_Shipping->calculate_shipping_for_package(Array, 0) #3 /home/username/public_html/wp-content/plugins/woocommerce/includes/class-wc-cart.php(1270): WC_Shipping->calculate_shipping(Array) #4 /home/username/public_html/wp-content/plugins/woocommerce/includes/class-wc-cart-totals.php(345): WC_Cart->calculate_shipping() #5 /home/username/public_html/wp-content/plugins/woocommerce/includes/class-wc-cart-totals.php(794): WC_Cart_Totals->get_shipping_from_cart() #6 /hom in /home/username/public_html/wp-content/plugins/woocommerce-table-rates/includes/class.tablerate.php on line 188