I have an early 2009 Mac Pro with OSX 10.9. I don't want to break anything so I haven't updated to Sierra but more and more apps are incompatible with my computer now.
I guess you already know that 10.9 is no longer supported, so you might want to consider to at least update to 10.10.
I have an early 2009 Mac Pro with OSX 10.9. I don't want to break anything so I haven't updated to Sierra but more and more apps are incompatible with my computer now.