In three prophecies in the unit of prophecies of consolation, Yirmiyahu foresees the changes that will take place at the time of the redemption.
The first prophecy deals with Israel being replanted in their land and the new relationship between the actions of the fathers vs. the consequences to the sons.
The second prophecy deals with a new covenant and its consequences. The difference between the old covenant and the new one relates not to the contents or to the addressee, but to the manner in which it will be made and its consequences.