Since major version updates always come along with breaking changes, CDBDriver tries to recognize the database version initially to take care of endpoint inconsistencies. To achieve this, the Legacy Mode was introduced.

When enabled, some API endpoints get changed to ensure full functionality. This is checked automatically within the constructor by invoking the info() method on the current instance.

Developers Annotation

Even if it's technically possible, I don't recommend connecting to databases on lower versions than v2. There is no guarantee that the legacy mode works as expected. Consider upgrading to a newer version of CouchDB.