I do not have any personal need for versions below 7.4 either, but I assume that some might still need PHP5.6 for some legacy applications. Obviously not recommended though as said release is EoL since almost 4 years already.
Going even further back than 5.6 is IMHO a waste of time, as I would suppose that the number of users still requiring such a setup are very very low, especially given that PHP 5.5 is already end-of-life since more than 6 years ago as mentioned in the first post too.