They get bumped. When you publish a new NDA version, the old document is marked superseded and existing reviewers lose proxy access on their next request. They see the new NDA text and have to re-sign before they can access the prototype again.
Each consent is tied to a specific document version (with a SHA-256 hash of the content), so you always know exactly which version someone agreed to.
I built ProtoWall (https://protowall.app), an auth and NDA wall that sits in front of your prototype. You invite someone by email, they log in via magic link, sign a versioned NDA, and get reverse proxied through to your app. No SDK, no middleware, no code changes on your end.
Built it because I was tired of the "just password protect it" workaround when sharing early stage work. Passwords get forwarded, and wiring up auth on something you'll throw away is wasted effort. I wanted a paper trail. Who saw what, when they signed, and a way to revoke access instantly.
Free tier gets you 1 project, 5 invites, default NDA template, and a 7 day audit log.
Each consent is tied to a specific document version (with a SHA-256 hash of the content), so you always know exactly which version someone agreed to.