How to send keystroke with shift modifier?
I never used this library, but in the header file there are this constants for modifiers:

#define MOD_CONTROL_LEFT    (1&lt;&lt;0)
#define MOD_SHIFT_LEFT      (1&lt;&lt;1)
#define MOD_ALT_LEFT        (1&lt;&lt;2)
#define MOD_GUI_LEFT        (1&lt;&lt;3)
#define MOD_CONTROL_RIGHT   (1&lt;&lt;4)
#define MOD_SHIFT_RIGHT     (1&lt;&lt;5)
#define MOD_ALT_RIGHT       (1&lt;&lt;6)
#define MOD_GUI_RIGHT       (1&lt;&lt;7)


and a function

void sendKeyStroke(byte keyStroke, byte modifiers)


so I would use this to send a key with Shift like this

sendKeyStroke(KEY_F2, MOD_SHIFT_LEFT);