if you're storing the raw binary rather than hex or base64: yeah. there are often no illegal values, so there's no way to safely extend it, unless you can diff

if you're storing the raw binary rather than hex or base64: yeah. there are often no illegal values, so there's no way to safely extend it, unless you can differentiate on length. for those, you have to leave versioning room up-front. even 1 bit is enough, since a `1` can imply "following data describes the version", if a bit wastefully in the long run.