Redwood Procurement RSSP in 25C - progressive or default replacement?

In this post by Oracle, it is made clear that there are two methods to enable RSSP Redwood Self Service Procurement. Either progressively where both UIs are available side by side, or as a replacmeent UI affecting all users.

We have opted for Approach 1 and have been enabling it it progressively across our requester base in Production.

Are we able to continue this progressive roll-out even after 25C, or will 25C enforce Approach 2 where RSSP will automtically become the only requisitioning experience for all our users?