XTCE12 — inability to describe sets of limits (alarms) and conversions (polynomials)

inability to describe sets of limits (alarms) and conversions (polynomials) and then select a set per parameter depending on mission phase (JWST)

JWST hold conversion and limits in a seperate file that are grouped. Certains "sets" can be used for different mission phases such as test, on-orbit and so on, or for any reason deemed appropriate. XTCE allows one to specify at MOST one of each of these per parameterType

Significant data model change, defer to future version

This would be a significant change in the data model in order to support a capability that is already supported via the ParameterType inheritance mechanism. The requested feature can be handled by the database modeling tools and still exchanged using the mechanism in XTCE. The requested feature is being deferred for consideration in a future revision.
What is called a mission phase here is called a context in XTCE. XTCE has a very robust capability to describe different alarms or calibrations in different Contexts.
Calibration and Alarm Sets are used in many ground systems that employ a relational data model. In actual space systems, calibrations and alarm sets are shared by Parameters when the Parameters of the same 'type'. For example, all voltage Parameters on a SpaceSystem will all have the same calibrations when the same voltage transducer is used. Because XTCE parameters are all declared from ParameterTypes, it is very easy to define a single 'VoltageType' with the calibration in the VoltageType and instantiate many Voltage Parameters.