This document lists the known differences in operation and functionality between PHost and HOST 3.2x. Some of these differences are matters in which, at the time PHost was initially written, the original HOST implementation was unknown and could not be determined by comparing input with results. In these instances, PHost has implemented similar functionality, but does not necessarily duplicate HOST results. Today, most of HOST's inner workings are known, so some of these differences may seem easy to "fix", but that would be counter-productive. The PHost rule set is well-established besides the HOST rules, and changing it would only make matters worse ("what are the alchemy rules of the day?").

These days, HOST doesn't get many updates, therefore it's PHost which keeps trying new rules, which - of course - differ from HOST. Some of the changes are also considered bugfixes in the original implementation.

The differences are grouped according to who is affected, the host or the player. Differences are grouped by the area of the game in which you will encounter it.