I know that since v0.66 you can edit the extra keys row as exposed in https://wiki.termux.com/wiki/Touch_Keyboard.
I immediately came back to the defaut v0.65 layout : ( extra-keys = [['ESC','/','-','HOME','UP','END','PGUP'],['TAB','CTRL','ALT','LEFT','DOWN','RIGHT','PGDN']] ).
nonetheless i couldnt set a key as shift.
i've tried 'SHIFT' or 'SHFT' or 'LSHIFT' but none of theese work.

is shift implemented and if it is what string is it mapped to?