for ubuntu 20.04 aarch64 on php 8.0 / 7.4 can resolved on dns_get_record.
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hm... but on RHEL still can resolved on this due already support php 8.0 in their changelog.
RHEL : https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html-single/8.6_release_notes/index#overview-major-changes
Oracle : https://docs.oracle.com/en/operating-systems/oracle-linux/8/relnotes8.6/ol8-features-changes.html#ol8-features-database
Including support latest mySQL 8.0 both.
RHEL : Chapter 2. Architectures - https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html-single/8.6_release_notes/index#architectures
Oracle Linux : Chapter 7 Release-Specific Information for Oracle Linux 8.6 (aarch64) - https://docs.oracle.com/en/operating-systems/oracle-linux/8/relnotes8.6/ol8-arm-only.html
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if issue on php.net (official) can your team create the ticket bug to them cause i personal create this issue maybe slow response reply form team php.net
Thanks.