# How to modify substrateNode code for extensibility of Delphinus Cross Chain System ## Change admins Changing admins means upgrade runtime. Increment the spec_version to specify the new runtime version.To upgrade the runtime, you must increase the spec_version. Save your changes and close the runtime/src/lib.rs file. Recompile and connect to the local node Verify that the local node continues to run in the first terminal. In the second terminal where you updated the runtime Cargo.toml and lib.rs files, recompile the runtime by running the following command cargo build --release --package node-template-runtime If a runtime upgrade requires changes to the existing state, it is likely to require storage migration. upgrade the runtime means uograde state You can't modify the storage. If you do that, the genesis hash will change. Which means it will be a totally different chain. Even though you apply this to all the nodes. The old state won't be kept/synced. The initial genesis state that all nodes in the network agree on. The genesis state must be established when the blockchain is first started and it cannot be changed thereafter without starting an entirely new blockchain. We cannot change chain spec?