The foregoing requirements in respect of any issue of revenue bonds or series thereof, may be contained in a single ordinance or in successive ordinances enacted, in either case, prior to the issuance of such bonds or of such series thereof.
The covenants, terms and provisions of the bond ordinance made for the benefit of obligees of the bonds shall constitute contractual obligations of the city subject to modification (with such limitations as may be specified in the bond ordinance) by agreement with a majority in interest of the holders or registered owners of the bonds or such larger portion thereof as may be provided in the bond ordinance.
53 P.S. § 15907