Existing functionality as requirements?
I'm wondering what other's think about a dilemma we are having amongst BA's in my organization. When documenting requirements for maintenance to our Legacy system, some BA's feel it is quite acceptable to include current functionality as a requirement if they feel that the enhancement requirements may cause that current functionality to be affected or removed.
An example would be something like "Retain current functionality that allows users to update termination date."
I don't necessarily agree with this, though at times it may be valid to express to the development team that the enhancement requirements should not affect current functionality.
Anyone have any comments how to communicate things like this?
MPS
What about in COTS SRS?
For your situation it seems to me entirely appropriate to document existing functionality. It sounds like your document will be the only record of what the app is actually supposed to do, and I believe it's vital to have that recorded somewhere. Isn't traceability necessary not only for initial requirements gathering, but in cases of change? I'm a relative newcomer to this field, and I suppose the original goals and functionality of the app would be an ideal reference when considering enhancements of any type.
I don't know if I agree with the approach of your teammates -- how traceable is the statement "Retain current functionality that allows users to update termination date" if it's not in an original SRS, numbered in some way? The original requirement is stated, but is it then buried in a change management doc?
As I've said, I'm a new BA, trying to compile an SRS for a COTS selection project. My projects so far have all consisted of a search for a new system to replace an old one. My struggle concerns the best way to document existing functionality if it is a feature common to all applications of its type. I'm tempted to separate, but still specify, these "expected" requirements, then follow them with the more detailed requirements that came from the users. As I haven't been able to find any guidance in published sources, any comments would be welcome.
This is my first post as well; if I should start my own thread to ask this question, please let me know!
Many thanks.