Thx pert.
I have Arduino 1.8.5 - so it is the latest one.
Arduino AVR Boards says Installed and no update button - it looks like is also OK.
But in the sketch I have:
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
So it looks I need this - or I'm doing something wrong?
Thx