On Windows it’s Ctrl+Alt, on Mac it’s simply Control (as opposed to the normal Mac counterpart, that would be Command-Option).
Thank you Daniel
Has this functionality been removed as of Version 2.2.10? It is not working for me now.
Weird - it works for me, I was just using it yesterday.
Definitely still works on mac here:
Shift+Alt+notename for higher
Ctrl+notename for lower
A few people have mentioned that they remap the +octave, -octave keystrokes.
I have them mapped to the + / - key on the number pad.
It is now so easy to move octaves, I don’t even remember how the other shortcuts work anymore.
you can also highlight a group of notes and hit +/- to move them all at once one or more octaves at a time.
shr23, you’re talking about the shortcuts for moving notes up and down after the fact
This thread is predominantly about the shortcuts for use during note input, before you input a note.
These shortcuts can’t be changed, as far as I can tell.
Hmmmm, not working for me but used to. I am not sure how to proceed to get things back correctly, as I try to add shortcut for Note Input/Octave Down, press Control, it does not get added to keystroke in Key Commands window. Totally lost. Would I have to somehow add a key command for each pitch A, B, C, D, etc??
shr23, pianoleo is correct in his interpretation of what I am talking about, but thanks anyway. (Don’t have a numeric keypad either) 
musicmaven, do these modifier keys work with some pitches but not others? If so, it may be that another program is “grabbing” one or more specific shortcuts.
Some voodoo going on, it is working now. I am not crazy, because this was definitely not working a few moments ago. Thanks everyone for your help (some good karma perhaps??)
I also use those shortcuts.
Personally I find it’s quicker to press a note letter like C followed by + or - on the keypad, than to type Ctrl-Alt-C or Shift-Alt-C with 3 fingers to force the C to be higher or lower than the previous note, especially after mapping the note duration numbers and accidentals onto the keypad as well.
Left hand on A-G on the main keyboard (and also the other nearby shortcuts like Q, T, S, V, etc), and right hand on the keypad is very quick - at least if you have already developed the hand independence by playing a musical instrument.
Absolutely.
You can also set key commands to push BEFORE inputing a note. I’ve set mine to ‘m’ and ‘k’ for lower and higher.
I have imported a score that has sections where the instrument needs to be moved up or down by an octave. Please tell me how to accomplish this.
Select the notes, and press Ctrl-Alt-up or -down to transpose them. (On Mac, Cmd-Alt-up)
From the beginning of time, I’ve used Ctrl-Alt-arrow up or down to shift the select notes an octave. For some reason, in the middle of the project, it stopped working. I can use Alt-Arrow keys fine. The Ctrl-Alt arrow is not working. I’ve saved the project and restarted to see if it would reset the default behavior, but it didn’t. The question is, could I have inadvertently turned it off? How do I get it back to the default behavior?
It seems that a recent Windows 10 or Intel graphics driver update has borked these shortcuts for a number of people.
Please see the helpdesk article.
On my Mac, I find that Shift-Option-[letter] for the upper octave register works as intended for every note except B. That combination has no effect.
I searched for a Shift-Option-B command I might have added in the past, including searching the whole Key Commands web page (which does include the commands I’ve added), without finding any duplication of this one. (I did add 2 commands to break and combine beams, but neither is this particular combination.) Has anyone else encountered something like this?
Yes. It’s a bug - unfortunately the operating system (or possibly Qt - I can’t remember) sees it as a dead key. There’s nothing that you can do about it (except assign a different shortcut), and there’s not much the development team can do about it either 