Isn't it annoying - if it's not broke don't fix it.  Here's what you need to do.   Tempo changes are now handled by the expression tool.  Click the expression tool and double click at the beginning of the measure you want the tempo change (or anywhere in the measure).  On the left choose tempo alterations.  On the bottom click Create Tempo Alteration.  Name it anything (or nothing).  Click Payback on the top.Click Type and choose tempo.  Set a value (like 60, which means quarter=60).  Click OK.  Assign it to a beat in the measure you want the tempo change.  Then right click on it in the score and unclick Show - if you don't what it to be seen.  Voila - life is good. Much more cumbersome than using the old tempo tool !!!

Thanks so much for your answer. I still do not see how to assign a number of measures with the new tempo. I can change one measure, but then it goes back to it's original tempo. How do I tell it how many measures I want that tempo to be, like in the old Finale?

I can see it changing but would not expect it to go back to the original tempo unless there is MIDI tempo data already in teh file that overrides it. You can check this by selecting the entire file and under Edit > Clear Selected Items choose all the MIDI items to clear.

I suggest trying this on a COPY of your file, just in case.

Sorry to say that didn't work either, but many thanks for your effort.  I'm calling Support tomorrow!