I disagree with their suggestion to comment out or remove old PHP code. People need to have a date and timestamp at their top of the articles AND state what ver

I disagree with their suggestion to comment out or remove old PHP code. People need to have a date and timestamp at their top of the articles AND state what version of PHP they are coding for. Information on older version should not be pruned as there are legitimate reasons to keep them. Not everyone is using PHP 7; what do you do when you inherit an older code base; what do you do when you just need to modify a few things on an older code base; what if you are trying to learn security based programming; what if you are trying to learn how to break into systems (to then learn how to protect them); what if PHP7 is not available or feasible for your project; etc.