Personally I'd do 7.2.2 -> 7.5.6 (global moderators group was added, PHP5.0 or newer) -> 7.7.5 (PHP5.4-PHP7.4) -> 8.0 (PHP7.1 - PHP8.1 Supported) -> 8.0.1 (overlays on 8.0.0)

The minimum required version of PHP in UBB.threads is:
v8.0.1 Can be run on PHP 7.1 - PHP 8.3
v8.0 Can be run on PHP 7.1 - PHP 8.1
v7.7.5 Can be run on PHP 5.4 - PHP 7.4
v7.7.0+ Can be run on PHP7
v7.6.0+ Requires PHP 5.3 or newer.
v7.5.9 Requires PHP 5.1.2.
v7.5.6 Requires PHP 5.0 or newer.
v7.5.0 Requires PHP 4.3.
PHP v7+ is only supported by UBB.threads v7.7.0+.

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