We have written init-script to create some contracts on bootstrap but now daml code is changes we want to update those contracts which were earlier created on bootstrap.
can anyone guide me on how to update those already existing contracts or how to archive those contracts from bootstrap script?
Welcome to the forum. To archive some contracts on the ledger you should be able to use the same method that you used to initialize the ledger with a set of contracts. E.g. if you used Daml Script to create the initial set of contracts you can use Daml script to archive these contracts. You will need to run this Daml Script with the same authority you used in the script that created the initial set of contracts, as you need the same authority (the authority of all the signatories of the contract) to create and to archive a contract. See the documentation for details on using Daml Script to modify the state of an already running ledger.
We are using canton script not daml script