1. The `convertException()` method has been removed from the `Driver` interface. The logic of exception conversion has been moved to the `ExceptionConverter` interface. The drivers now must implement the `getExceptionConverter()` method.
2. The `driverException()` and `driverExceptionDuringQuery()` factory methods have been removed from the `DBALException` class.
3. Non-driver exceptions (e.g. exceptions of type `Error`) are no longer wrapped in a `DBALException`.
## BC BREAK: More driver-level methods are allowed to throw a Driver\Exception.