Interrelationship between EC Reg 1612/68 and Directive 2004

Hey, anyone has any ideas how does Directive 2004 affect the Regulation 1612? I know that the Directive repealed most of old law and just amended Regulation 1612 in part.

What can the EEA citizen rely on as a worker? Directive 2004 or Regulation 1612 or both? Reg 1612 has extensive case law, would that apply to the Directive as well?

Any clarification would be helpful.