http://isdb4l77sjqoy2qq7ipum6x3at6hyn3jmxfx4zdhc72ufbmuq4ilwkqd.onion/blog/20230328-simplex-chat-v4-6-hidden-profiles.html
If multiple profiles are hidden with the same passphrase they will all show in the list when you enter it. It's important to remember that these hidden profiles are still stored locally on your device, so if somebody has access to your chat database (they need to know database passphrase, that is independent from device PIN or profile passphrases) or to chat console in the app, they will be able to access these profiles data and reset their passwords.