I am very interested in your solution to ISO procedures. I have seen this topic before in this forum, so maybe others are also interested. I know that others also used Tadabase for procedures.
An ISO procedure can exist of multiple versions in the lifetime of the procedure. There is a restriction though: only one version of a procedure can be valid. Next to the valid version you will have archived (previous) versions, and you can have 1 draft version, which is editable and will eventually replace the current valid version.
If this is easy: you might add following restriction: it would be great if a draft version of this procedure gets released (turned to valid) and at the same time (through rules for example) the valid version gets automatically archived, so change the current valid version from valid to archive. And off course the draft version to valid.
Another feature could be: archive and valid versions can not be edited, only draft version are editable.
And if you still have time left: procedures can only be edited by users who are authorized to do this. And if you still have time left: an audit trail would be great, so you can see who edited the procedure and who changed versions of the procedure from draft to valid.