Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).

Motivation

As the moment the IQ is only thrown InvalidStateStoreException for all errors.

Public Interfaces

...

That means we cannot handle different types of errors. We should throw different exceptions for different types.

There two types of IQ errors:

What impact (if any) will there be on existing users?
If we are changing behavior how will we phase out the older behavior?
If we need special migration tools, describe them here.
When will we remove the existing behavior?Because no classes will be removed, this change will be fully backward.

TBD