What toilet was replaced, uopstairs or downstairs, to fix the bubbling problem whenever the upstairs toilet was flushed?

My crystal ball is broken today. To what or whom are you referring. Previous post? Problem at your house?

What toilet was replaced, upstairs or downstairs, to fix the bubbling problem whenever the upstairs toilet was flushed? Run that by me one more time!
If you had a plumber that sold you a new toilet to fix a blockage then fire the plumber and sue the company her works for. Or you could let us in on what you're talking about. Back to you, Tpm