ICU and the INTL_IDNA_VARIANT_2003 deprecation

Hello, It seems that an important detail was missed in the RFC to deprecate INTL_IDNA_VARIANT_2003 in PHP 7.2.0 (and later remove it). The only other option available - INTL_IDNA_VARIANT_UTS46 - may not be available at all, as PHP has ICU 4.0 as its minimum requirement, but support for UTS#46 was introduced by ICU 4.6 ... As a result, there may be systems where having a clean call to idn_to_ascii(), idn_to_utf() is impossible. I'm all for following deprecations by upstream, but I didn't find any mention of this scenario in the discussions. I'm assuming nobody has considered it and we're in a bit of a mess right now, so ... My immediate thought is to simply bump the ICU version requirement, but I have no idea what kind of an impact that would have. [1] RFC: https://wiki.php.net/rfc/deprecate-and-remove-intl_idna_variant_2003 [2] ICU 4.6 release: http://site.icu-project.org/download/46 Cheers, Andrey.