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
Explicitly require preservation if the feature might be dropped
If the BA thinks that existing functionality will be at risk to change or go away, then it's beneficial to expressly require its preservation or its removal. To omit such a requirement delegates the decision to the developer. The developer may see removal as the obvious choice (because it looks like the new "date last worked" field will replace the old "termination date" field) while the user expects the new application to have both fields available.