WordPress gets constantly updated and every update brings new features and fixes bugs.

Will the plugin no longer work with a WordPress version that is no longer supported?

No, if the plugin worked in the past it will most likely work in the future.¬†Sometimes features not available in this version will cause an error that no longer gets fixed.¬†Also, there’s no dedicated test for the deprecated version.

In general, I recommend keeping your WordPress site and its plugins up to date to prevent security vulnerabilities.

Read more about updating WordPress.