The state does hereby pledge to and agree with the holders of any notes or bonds that the state will not limit or alter the rights hereby vested in the municipality to fulfill the terms of any agreements made with said holder thereof, or in any way impair the rights and remedies of such holders until such notes and bonds, together with the interest thereon, with interest on any unpaid installments of interest, and all costs and expenses in connection with any action or proceeding by or on behalf of such holders, are fully met and discharged. Municipalities are authorized to include this pledge and agreement of the state in any agreement with the holders of such notes or bonds.