As we observed in the early part of this chapter, the smart contract binding peers on a shared channel is subject to change for a variety of reasons ranging from code fixes to evolving needs of the participants. Regardless of the reason, the mechanism offered by Hyperledger Fabric and the semantics of the change remain constant. The mechanism is what we we'll demonstrate in this section.

Closely associated with the smart contract, at least in the Fabric view of a blockchain, is the endorsement policy that must be satisfied for the result of a transaction to be committed to the shared ledger. As we will see, the same mechanism that can upgrade a smart contract can be used to modify the endorsement policy too.