Hello Apps and their extensions are able to communicate with each other by reading/writing data stored in a shared group location. However this isn't the case with the the Live Caller ID Extension - if data is written to group defaults for example (as opposed to standard defaults) by the app, then that data isn't readable by the Caller ID extension.
This has the consequence that its not possible for a user to dynamically switch which data set the extension connects to. Consider the use case where the Live Caller ID Server has one data set where callers are not blocked, and another where they are blocked, then the caller id extension can route different requests to different datasets based on the "user tier". However as the extension can't read data from the shared group then the app can't communicate user preferences to the extension, therefore the switching isn't possible.
Is this by design or due to the immaturity of the feature? If its by design, then it means the use case outlined above isn't possible, and thus greatly reduces the possible functionality of the Live Caller Id feature.
(It would be possible for the app to install multiple extensions, each of which connects to a different data set by specifying a different user tier, but the user having to flip these one and off within the Settings app is a dreadful user experience).