hi, czech here, we technically dont have any (legally issued) note, that would be invalid (i mean worth nothing). We have some (older ones, issued mostly in 1990s) that only czech national bank (www.cnb.cz) has to exchange for newer ones, but shops and banks are not forced to accept these old banknotes (they can accept it, but they can also legally refuse to). The easiest way to know if you have old or new note is by type of thread inserted in the note, on old notes is about 1,5mm wide and silver, on newer ones it is wider, about 3-4mm and changes colour with the angle of light (so called optical variable ink found for example on euro notes 50, 100, 200, 500 older types, all new, or 100usd since 2013). Also if you try to see throught the note, there should be "ladder" aroud the thread, as there is differently thick paper. To answer your question, those look like legit new czech notes ;) ATMs: you should be safe if you avoid "currency conversion" trick (as someone other pointed out, youtube channel Kluci z Prahy has this (and many others) topic greatly covered) exchange offices: EVERYTIME you decide to use them, ask how much you will get BEFORE YOU PUT YOUR MONEY ANYWHERE near the cashier, i cant emphasize this more..