| ⇢ | A | DummyDriver added |
| ⇢ | A | DummyDriver.__init__() added | |
| ⇢ | A | DummyDriver._read() added | |
| ⇢ | A | DummyDriver._isOpen() added | |
| ⇢ | A | DummyDriver._write() added | |
| ⇢ | A | Driver.byteString2String() added | |
| ⇢ | A | DummyDriver._close() added | |
| ⇢ | A | DummyDriver._open() added | |
| ⇢ | A | Driver.splitN() added | |
| B | ↘ | F | Driver.read() got worse |