This is work in progress... Section numbers refer to the Z.151 (URN) standard.
Mismatches
6: GRL Beliefs are IntentionalElements in Z.151, whereas they are not in jUCMNav (they are a type of GRLNode, and hence cannot be associated with a value in a strategy)
6.1.5: Concern: Z.151 targets URNmodelElement, jUCMNav targets them now but also targets IURNDiagram
7.4.6: DecompositionType is different. Z.151 has {AND, XOR, IOR}, and jUCMNav has {And, Or, Xor}.
7.5.2: EvaluationStrategy in Z.151 may be associated to many StrategiesGroup in Z.151, but to only one in jUCMNav.
7.6.13 Comment: Z.151 has Comment (comment boxes) attached to UCMmap and GRLspec, jUCMNav has it attached to IURNdiagram (with a different role name)
9: Handling of URN data model (syntax) by jUCMNav (I believe there are small differences, e.g. postconditions in Z.151, "else" in jUCMNav)
Many mismatches related to how indicators are supported
Many mismatches related to how contribution contexts are supported
In Z.151 but not in jUCMNav
GRLnode has a size (width/heigth) in Z.151 but not in jUCMNav (stored as metadata)
NodeConnection is a URNmodelElement (whereas it is not in jUCMNav)
7.6.1 ConcreteGRLspec: Z.151 supports visualization of XOR/IOR as means-end
8.2.1: UCMmap singletons (in the metamodel but unused)
8.4.2: ComponentType (in the metamodel but unused and no GUI)
8.6.1: Workload decomposed in Z.151 but not in jUCMNav
9: Syntax for previous values of variables in post-conditions
In jUCMNav but not in Z.151
ScenarioStartPoint and ScenarioEndPoint
An EvaluationStrategy can include other ones
EvaluationRange in strategy evaluations
Everything related to aspects
Everything related to failure points
Everything related to Feature Models, CORE, Activity Theory diagrams (ASD)
Interfaces for nodes, diagrams, containers, connections, container references
Deprecated features in jUCMNav
GRL IntentionalElement's priority and criticality attributes