I purchased CouponXL theme that only supports till wordpress 4.9 version. But I have wordpress 5.1 version. So Themeforest will help me by providing CouponXL theme coding that support wordpress 5.1 or above?
Theme Author responsible for theme update to make compatibility with latest version WordPress. So, the best way to get the support is Contact your purchased Theme Author and ask them when they will plan to make theme compatible with latest wp.