Important: #90911 - Package algo26-matthias/idna-convert removed

See Issue #90911

Description

The TYPO3 core dependency / composer library algo26-matthias/idna-convert does not support PHP 7.4 in its currently used version. It has been removed from the composer dependencies and the current used code is placed into typo3/sysext/core/Resources/PHP/idna-converter to support directly usage of that package.

This makes it possible to use TYPO3 v9 with umlaut domain validation (e.g. also when using EXT:form with sending an email to someone with a umlaut domain as recipient) in conjunction with TYPO3 v9 and PHP 7.4.

If the PHP code of the package is used directly by third-party extensions, this will have no further side effects, as the TYPO3 core still provides the source code, but be aware will not work with PHP 7.4.

If you like to use the package in a newer version, follow the docs https://idnaconv.net/docs.html and add the custom PHP code yourself.

If you are using the TYPO3 API GeneralUtility::idnaEncode() everything works as before, but now also with PHP 7.4 support.