Our JCR implementation updates the "/jcr:system/dna:namespaces" and "/jcr:system/nodeTypes" areas as the namespaces and node types change, respectively. The federation connector doesn't support updates, and using the federation connector with our JCR results in errors running the repository examples for the Getting Started guide.

These updates follow a specific and limited pattern: all of the updates are within a single projection, and in these cases the update requests can be transformed and sent down to the one connector for the projection. This very limited scenario would go a long way, and its pretty straightforward.