Tiki 24.0 LTS will be released in February 2022. It is a Long Term Support (LTS) version and will be supported until February 2027 as per the Tiki lifecycle policy
As of 2021-07-18, it is not clear if PHP 8.x will be supported. All the Tiki code was updated long before the release of PHP 8.0, but some of the dependencies have issues.
Apart from page load time, boomerang measures performance timings, metrics and characteristics of your user's web browsing experience