getting warnings on php 7.4

I have version 5.4.7.4 installed for slider revolution and it is giving warnings when I switch to php 7.4.

Warning** : “continue” targeting switch is equivalent to “break”. Did you mean to use “continue 2”? in /homepages/4/d737329001/htdocs/clickandbuilds/qbarinsights/wp-content/plugins/revslider/includes/operations.class.php on line **2851

Warning** : “continue” targeting switch is equivalent to “break”. Did you mean to use “continue 2”? in /homepages/4/d737329001/htdocs/clickandbuilds/qbarinsights/wp-content/plugins/revslider/includes/operations.class.php on line **2855

Warning** : “continue” targeting switch is equivalent to “break”. Did you mean to use “continue 2”? in /homepages/4/d737329001/htdocs/clickandbuilds/qbarinsights/wp-content/plugins/revslider/includes/output.class.php on line **3708

When I want to update the plugin then it prompts to buy,
Is buying the only solution to fix this issue?

I believe Slider Revolution works fine with PHP 7.3 version. You can wait for the theme upgrade for a free solution to check if the latest version ( if there’s any update ) solves the problem or you can purchase your own copy.