Magento 2.2.6 Configurable Product How to Show Old Price & Special Price?

Copy final_price.phtml from

Vendor/magento/module-configurable-product/view/base/templates/product/price/final_price.phtml

to

Vendor/theme/Magento_ConfigurableProduct/templates/product/price/final_price.phtml

change (around line 22)

<?php if (!$block->isProductList() && $block->hasSpecialPrice()): ?>
with
<?php if ($block->hasSpecialPrice()): ?>

(special_price will display)

and replace
<span class="old-price sly-old-price no-display">
by
<span class="old-price sly-old-price">