Mass. Gen. Laws ch. 260, § 19A
(a) As used in this section the following words shall, unless the context clearly requires otherwise, have the following meanings:
''Euro'', the currency of participating member states of the European Union that adopt a single currency in accordance with the Treaty on European Union of February 7, 1992.
''Introduction of the euro'', the implementation from time to time of economic and monetary union in member states of the European Union pursuant to the Treaty on European Union of February 7, 1992.
''ECU'' or ''European currency unit'', the currency basket that is from time to time used as the unit of account of the European Community as defined in European Council Regulation (EC) No. 33 20/94.
(e) Substituted currency shall not change contract requirements. The following shall not have the effect of discharging or excusing performance under any contract, security, or instrument, or give a party the right unilaterally to alter or terminate any contract, security, or instrument: