XF 2.2 "INTL_IDNA_VARIANT_2003 is Deprecated" after XF 2.1 to XF 2.2 upgrade

[CStrategies]

PHP version: 7.2.34
MySQL version: 10.2.34
XF 2.2.13

After upgrading from XF 2.1 to XF 2.2.13, when attempting to add a resource with the resource manager that includes URLs in the fields, we get an error ErrorException: [E_DEPRECATED] idn_to_ascii(): INTL_IDNA_VARIANT_2003 is deprecated src/XF/Util/Url.php:28.

Similar errors pop up from various places all tracing back to the idn conversions in XF/Util/Url. I'm aware I could silence these errors by turning off development mode, but wondering why there are deprecated URL conversion functions in XF 2.2.13 to begin with. Or am I misunderstanding what is taking place?

 

[Kirby]

PHP version: 7.2.34

That's the problem.
Upgrade to PHP 8.0 and the error will be gone.

PHP: idn_to_ascii - Manual

PHP is a popular general-purpose scripting language that powers everything from your blog to the most popular websites in the world.

www.php.net

XenForo doesn't set parameter variant, so depending on the PHP version it might be the deprecated default INTL_IDNA_VARIANT_2003.

A workaround could be to explicitly set INTL_IDNA_VARIANT_UTS46 if that is available and fallback to bundled Symfony polyfill-intl-idn if it is not.