Hello! We’d like to acknowledge the unusual situation here, where Season 1 gear upgrades are no longer available.
You’ll find that world content in in the new zone gives Season 2 gear, which can be upgraded. There’s some awkwardness to the one week transition period, but as of the patch going live, we need the world to be in a “Season 2” state in terms of currencies so that the Undermine zone content can function as expected. At the same time, we’re keeping Season 1 instanced content active just to make sure players have a few more days to finish some of the achievements that are still available.
We don’t currently have a way, technically, to keep Season 1 gear upgradeable after moving into a Season 2 currency ecosystem, which we have now done.
We understand that this can be confusing and frustrating, and we’ll continue to discuss further improvements to season transitions in the future.