Choose which version applies to you.

The version for people below level 50 only has one change,
that is that heat level 6 still gets displayed as heat level 5.
The reason for this is that level 6 breaks the REP multiplier
and that also makes it much harder to level up.

The actual difficulty and heat levels themselves however are
NOT affected, they are the same for both version, the only
difference is the number in the heat bar.