The event log of key strokes is the source of truth for the entire document editing system, I can't think of a reason why one can't rewrite history after a certain time, except to say that this requirement will probably impact a lot of sub-systems from storage to UI, that now have to keep working under historical revisionism. I certainly haven't bothered doing that.

It's probably one of those situations where you'd write a "Diversion Report" for the security team where you talk about limited assets at rist and a huge investment in engineering resources.