@AffordableTech said in Issue after updating from 1.5 to 2.1.1: Hi @tekka , When you say "describe your HW setup", I'm not quite sure what your require? Do you need the specific configuration/wiring of the various eleven nodes, or are your referring to the development PC which the Arduino IDE is running on? Paul, @tekka was asking about your node h/w configuration; in particular how the radio is wired. The Arduino IDE and Boards Manager that you are using should be fine.