In Season 5, the power level cap in Destiny 2 is supposed to be increased. However, even though Season 5 is already underway, the new max power level is not yet active. Now Bungie has clarified the situation.
Recently, the developers of Destiny 2 announced that as part of the Season 5, the Season of the Forge, the maximum power level of the Guardians will rise – as a free update for all owners of the Forsaken expansion. The power level cap is set to increase by 50 points per season; in the current season, that would be 650. However, the change is still awaited.
New Power Level Cap in Season 5 – What You Need to Know
This is why many players are confused: Bungie’s announcement has caused confusion among players. After all, Season 5 has already begun on November 27. Progressing in power level beyond the current cap of 600 is currently impossible.
In the Gameplay Calendar, a kind of roadmap for the second year of Destiny 2, the feature is listed without a specific date for the period from December 2018 to February 2019.

This is what Bungie says: Now Bungie has cleared up all uncertainties in its current “This Week at Bungie” blog (TWaB) and revealed further details about power level progression.
The new cap will come with update 2.1.1. This will be the update that is released next Tuesday, December 4, with the launch of the first premium DLC “The Black Armory“. The new level cap can then be reached by all owners of Forsaken; the Annual Pass is not required for this.

The soft cap will remain at power level 500 – just like in the Forsaken expansion. A soft cap is a kind of limit up to which players level relatively quickly. Because loot up to this limit can be found almost everywhere.
After that, you will only find power upgrades, so-called powerful rewards, through specific sources, of which the pool is limited. This pool remains unchanged for all owners of Forsaken. Buyers of the Annual Pass will receive additional new sources for powerful gear.
For players under a power level of 550, Prism Engrams will drop more frequently and provide a higher power increase so they can reach endgame levels faster.
New information about the level requirements in the raid: In light of the new power level cap, the studio also discussed the power level requirements for the upcoming new raid “Scourge of the Past”. The recommended power level will be 640 – only 10 levels below the new level cap.

However, there will not be a minimum level required to enter the raid. The further the guardians progress within the three days of preparation, the easier the first foray into the new raid should be for them. This starts on December 7, 2018, at 6 PM our time.
By the way: Actually, the veteran rewards were also supposed to be delivered with update 2.1.1 on December 4 as a token of gratitude to all players who played Forsaken until October 16, 2018. This date has now been postponed due to technical difficulties to December 18.