In Diablo 4: Vessel of Hatred and Season of Hatred Rising, there will be some changes to the Difficulty Levels and how they work. The biggest change from the Season 6 PTR is that the Penitent level will be freely accessible to everyone at level 1 who has completed the Diablo 4 base campaign (or checked the box on the character creation screen to skip the campaign).
Patch Notes for 2.01/2.02 Patch 2.01/2.02 Livestream
In the Patch 2.01/2.02 Livestream, the Developers warn that anybody who thinks they can just jump into the Penitent difficulty level in marginal gear will be in for a deadly surprise. They made this change because they wanted to open Penitent up for those who like an extreme challenge. Previously, in the Season 6 PTR, you had to be level 50 to access Penitent.
This is what can happen to an under-geared character in the Penitent difficulty level.
Blizzard has changed the names of the first 4 difficulty levels:
There are 8 difficulty levels in total, with the hardest four being called Torment 1 — 4.
An important change to monsters in the various difficulty levels was announced. In the Patch Notes Blizzard stated:
Starting in Season 6, the monster intensity will no longer scale until you reach the Torment levels. Monster intensity is the function of monsters becoming stronger, with better ranged-attack accuracy, and having shorter cooldowns. This scaling has been removed from non-Torment difficulties.
The 8 new difficulty levels coming to Diablo 4.
The other changes in the 2.01/2.02 Patch Notes and Livestream that are related to difficulty levels include: