now, which ones should you consider using? the problem that these apps are trying to solve is that there's no common way to upload certification to airlines. and some airlines have decided to trial the iata travel pass. you upload the certification for your tests, vaccines and so on to it and that's then transmitted to the airline. it's still basically in trial form at this stage, but it's really promising. so, having it in one centralised system, which you would hold on your phone like any other app, would be sensible. i think this will become a part of — a part of travel life, in the way that perhaps, ten or 15 years ago, it would have been completely unthinkable that we all use mobile check—in, right? and show boarding passes on our phones or watches, and a computer in your phone that's powerful enough to do so, it's a fairly new innovation. as with so much else in aviation, covid has proven a real accelerator here. last but not least, i have i have the thermo smart