There is a significant risk, that rooms from the upcoming underworld kingdom will be included into the drawing pool of Underspire during its introduction week, as they have been last time, even before they start existing on that week’s friday.
Which means, defeating the replacement fight of four Ogres will bug out the spire.
As you may notice, the week in question starts on 25th december.
Do I need to say any more than that?
i like that idea of preemptive warning, i should do a whole preemptive bug list i guess this week 
I see the irony in your answer. But I say (no irony included):
If Devs read it it’s for good.
I spoke with the team about this and the Room data for Nightmare Circus is actually already in the game and there were changes made in 7.2 to make sure unreleased rooms wouldn’t be grabbed by the Underspire.
They’re going to triple check all the release dates on everything as we had some schedule shuffles for December and January.
So at the risk of jinxing anything it should go smoothly 
For comparison, on Switch we had Court of Foxes rooms in Underspire (and with zero problems) for quite some time before Vulpacea and its faction debuted.