There is a format called Premodern which uses sets from 4th Edition until Scourge. Modern Magic lacks such rules as mana burn and combat damage on the stack. What Magic rules flavour should I be using when playing Premodern?
The site you link to suggests the use of contemporary magic rules, and also gives a list of reasons why:
The contemporary rules are better
It’s confusing to use different rules in different formats
Contemporary rules enables digital and sanctioned play
There is no natural set of old rules
Using a mix of contemporary and old rules sets is inelegant
There have been so many changes to the rules that they are more of a continuum than a set of clearly defined points, and the choice of which rules to include is essentially arbitrary.
The most clearly recognizable landmark change was the 6th edition overhaul that introduced the stack among many other changes. Before then, the game was sufficiently different as to be a different game, which means you should expect a significant learning curve if you want to play faithfully by the older rules, and you can't expect too much outside support in case rules questions do arise.