Can we please do a workaround for this until it is fixed? I can't leave my machines while they're updating and have to keep babying them, which is a massive waste of my time.
Specific suggestion, this flag: --fallback fall back to building when the substituter fails This "unimplemented" error is a substituter failure, so if it fails it should fall back to building the package, no? Instead the entire command fails and the upgrade is aborted.
