As above! Be honest with yourself about the 'Why?'
The reason why, is that having dusted off my relatively old training bike, frame about 15 years old, group set nearer to 20, I thought I’d upgrade it. Essentially there’s nothing wrong with the frame ( Racelight TK2) or most of the components. For relativity little money, I planned to put 105 11 speed on it and at the same time a shorter stem, (not as flexible as I once was).
Following input by those above, (and thank you for your input), I will probably go down the Sora 9 speed shifter route, keeping all the serviceable items. The current 9 speed shifters are on their last legs, cosmetically and mechanically.