Among the numerous things I did not foresee, narrow rollout of ’phone OS updates as a bulwark against illiberalism must rank fairly high:
In order to download Excelsior Pass on your phone, you need the latest version of Android or iOS. For users of phones that are more than 4-5 years, this means you will not be able to access the application. If you have an iPhone 6 or earlier, you can’t download Excelsior Pass because it only runs on the latest operating system, which doesn’t work on these older phones.
I’d hazard a guess that the reason this didn’t come up at the design stage is that ostracising people is the entire purpose of the app. I should think creating a two-tier society wasn’t included among the failure conditions for the same reason the Sony rootkit wasn’t held back on account of being insecure.
Update: in related news, anything you may hitherto have read about the cashless society is also coming to look premature.