Imagine this: You are working on a already developed system in a stable release and now there is a change request coming up. Do you need to rewrite/change the requirement specification (and update the document to a new version)?
Note: I am very sorry if this is the wrong place for this question I carefully browsed http://stackexchange.com/sites#technology and this one seems to match the most.
Yes, you do because otherwise nobody will be able to track the changes of the system, and know how your system is supposed to work. Make sure that you mark the change section in the history of the document.
It depends.
If it's a change that affects the requirements, then yes, the document needs to be updated and versioned. But there are changes that don't affect the requirements. In that case, it might mean that the document has a hole and it should be added. Or it might mean that the change really doesn't affect the requirements and the document is fine.
Some change requests turn out to be data issues -- they don't affect the document. Some are minor tweaks that aren't documented anyway (perhaps the drop list doesn't fit when the screen resolution is set in some way, and the document never got anywhere near detailed to talk about screen resolutions or did more than mention that that field has a drop list filled by some source).
Read the document. If the change makes anything in the document incorrect, then update the spec. If the change is something that you wish you'd known about, something that would be useful to people in the future, then add it to the spec.
No, you don't need to rewrite the requirement specification, particularly if you are working with a "stable release" as you said.
However, you probably should update the system's documentation, user manuals or similar.
