> ## Documentation Index > Fetch the complete documentation index at: https://docs.cosmos.network/llms.txt > Use this file to discover all available pages before exploring further. # Migrations > This guide provides instructions for migrating 08-wasm versions. This guide provides instructions for migrating 08-wasm versions. Please note that the following releases are retracted. Please refer to the appropriate migrations section for upgrading. ```bash theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}} v0.3.1-0.20240717085919-bb71eef0f3bf => v0.3.0+ibc-go-v8.3-wasmvm-v2.0 v0.2.1-0.20240717085554-570d057959e3 => v0.2.0+ibc-go-v7.6-wasmvm-v1.5 v0.2.1-0.20240523101951-4b45d1822fb6 => v0.2.0+ibc-go-v8.3-wasmvm-v2.0 v0.1.2-0.20240412103620-7ee2a2452b79 => v0.1.1+ibc-go-v7.3-wasmvm-v1.5 v0.1.1-0.20231213092650-57fcdb9a9a9d => v0.1.0+ibc-go-v8.0-wasmvm-v1.5 v0.1.1-0.20231213092633-b306e7a706e1 => v0.1.0+ibc-go-v7.3-wasmvm-v1.5 ``` ## From ibc-go v8.4.x to ibc-go v9.0.x ### Chains * The `Initialize`, `Status`, `GetTimestampAtHeight`, `GetLatestHeight`, `VerifyMembership`, `VerifyNonMembership`, `VerifyClientMessage`, `UpdateState` and `UpdateStateOnMisbehaviour` functions in `ClientState` have been removed and all their logic has been moved to functions of the `LightClientModule`. * The `MigrateContract` function has been removed from `ClientState`. * The `VerifyMembershipMsg` and `VerifyNonMembershipMsg` payloads for `SudoMsg` have been modified. The `Path` field of both structs has been updated from `v1.MerklePath` to `v2.MerklePath`. The new `v2.MerklePath` field contains a `KeyPath` of `[][]byte` as opposed to `[]string`. This supports proving values stored under keys which contain non-utf8 encoded symbols. As a result, the JSON field `path` containing `key_path` of both messages will marshal elements as base64-encoded bytestrings. This is a breaking change for 08-wasm client contracts and they should be migrated to correctly support deserialization of the `v2.MerklePath` field. * The `ExportMetadataMsg` struct has been removed and is no longer required for contracts to implement. Core IBC will handle exporting all key/value pairs written to the store by a light client contract. * The `ZeroCustomFields` interface function has been removed from the `ClientState` interface. Core IBC only used this function to set tendermint client states when scheduling an IBC software upgrade. The interface function has been replaced by a type assertion. * The `MaxWasmByteSize` function has been removed in favor of the `MaxWasmSize` constant. * The `HasChecksum`, `GetAllChecksums` and `Logger` functions have been moved from the `types` package to a method on the `Keeper` type in the `keeper` package. * The `InitializePinnedCodes` function has been moved to a method on the `Keeper` type in the `keeper` package. * The `CustomQuerier`, `StargateQuerier` and `QueryPlugins` types have been moved from the `types` package to the `keeper` package. * The `NewDefaultQueryPlugins`, `AcceptListStargateQuerier` and `RejectCustomQuerier` functions have been moved from the `types` package to the `keeper` package. * The `NewDefaultQueryPlugins` function signature has changed to take an argument: `queryRouter ibcwasm.QueryRouter`. * The `AcceptListStargateQuerier` function signature has changed to take an additional argument: `queryRouter ibcwasm.QueryRouter`. * The `WithQueryPlugins` function signature has changed to take in the `QueryPlugins` type from the `keeper` package (previously from the `types` package). * The `VMGasRegister` variable has been moved from the `types` package to the `keeper` package. ## From v0.3.0+ibc-go-v8.3-wasmvm-v2.0 to v0.4.1-ibc-go-v8.4-wasmvm-v2.0 ### Contract developers Contract developers are required to update their JSON API message structure for the `SudoMsg` payloads `VerifyMembershipMsg` and `VerifyNonMembershipMsg`. The `path` field on both JSON API messages has been renamed to `merkle_path`. A migration is required for existing 08-wasm client contracts in order to correctly handle the deserialization of these fields. ## From v0.2.0+ibc-go-v7.3-wasmvm-v1.5 to v0.3.1-ibc-go-v7.4-wasmvm-v1.5 ### Contract developers Contract developers are required to update their JSON API message structure for the `SudoMsg` payloads `VerifyMembershipMsg` and `VerifyNonMembershipMsg`. The `path` field on both JSON API messages has been renamed to `merkle_path`. A migration is required for existing 08-wasm client contracts in order to correctly handle the deserialization of these fields. ## From v0.2.0+ibc-go-v8.3-wasmvm-v2.0 to v0.3.0-ibc-go-v8.3-wasmvm-v2.0 ### Contract developers The `v0.3.0` release of 08-wasm for ibc-go `v8.3.x` and above introduces a breaking change for client contract developers. The contract API `SudoMsg` payloads `VerifyMembershipMsg` and `VerifyNonMembershipMsg` have been modified. The encoding of the `Path` field of both structs has been updated from `v1.MerklePath` to `v2.MerklePath` to support proving values stored under keys which contain non-utf8 encoded symbols. As a result, the `Path` field now contains a `MerklePath` composed of `key_path` of `[][]byte` as opposed to `[]string`. The JSON field `path` containing `key_path` of both `VerifyMembershipMsg` and `VerifyNonMembershipMsg` structs will now marshal elements as base64-encoded bytestrings. See below for example JSON diff. ```diff expandable theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}} { "verify_membership": { "height": { "revision_height": 1 }, "delay_time_period": 0, "delay_block_period": 0, "proof":"dmFsaWQgcHJvb2Y=", "path": { + "key_path":["L2liYw==","L2tleS9wYXRo"] - "key_path":["/ibc","/key/path"] }, "value":"dmFsdWU=" } } ``` A migration is required for existing 08-wasm client contracts in order to correctly handle the deserialization of `key_path` from `[]string` to `[][]byte`. Contract developers should familiarize themselves with the migration path offered by 08-wasm [here](/ibc/v10.1.x/light-clients/wasm/governance#migrating-an-existing-wasm-light-client-contract). An example of the required changes in a client contract may look like: ```diff theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}} #[cw_serde] pub struct MerklePath { + pub key_path: Vec, - pub key_path: Vec, } ``` Please refer to the [`cosmwasm_std`](https://docs.rs/cosmwasm-std/2.0.4/cosmwasm_std/struct.Binary.html) documentation for more information. ## From v0.1.1+ibc-go-v7.3-wasmvm-v1.5 to v0.2.0-ibc-go-v7.3-wasmvm-v1.5 ### Contract developers The `v0.2.0` release of 08-wasm for ibc-go `v7.6.x` and above introduces a breaking change for client contract developers. The contract API `SudoMsg` payloads `VerifyMembershipMsg` and `VerifyNonMembershipMsg` have been modified. The encoding of the `Path` field of both structs has been updated from `v1.MerklePath` to `v2.MerklePath` to support proving values stored under keys which contain non-utf8 encoded symbols. As a result, the `Path` field now contains a `MerklePath` composed of `key_path` of `[][]byte` as opposed to `[]string`. The JSON field `path` containing `key_path` of both `VerifyMembershipMsg` and `VerifyNonMembershipMsg` structs will now marshal elements as base64-encoded bytestrings. See below for example JSON diff. ```diff expandable theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}} { "verify_membership": { "height": { "revision_height": 1 }, "delay_time_period": 0, "delay_block_period": 0, "proof":"dmFsaWQgcHJvb2Y=", "path": { + "key_path":["L2liYw==","L2tleS9wYXRo"] - "key_path":["/ibc","/key/path"] }, "value":"dmFsdWU=" } } ``` A migration is required for existing 08-wasm client contracts in order to correctly handle the deserialization of `key_path` from `[]string` to `[][]byte`. Contract developers should familiarize themselves with the migration path offered by 08-wasm [here](/ibc/v10.1.x/light-clients/wasm/governance#migrating-an-existing-wasm-light-client-contract). An example of the required changes in a client contract may look like: ```diff theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}} #[cw_serde] pub struct MerklePath { + pub key_path: Vec, - pub key_path: Vec, } ``` Please refer to the [`cosmwasm_std`](https://docs.rs/cosmwasm-std/2.0.4/cosmwasm_std/struct.Binary.html) documentation for more information. ## From ibc-go v7.3.x to ibc-go v8.0.x ### Chains In the 08-wasm versions compatible with ibc-go v7.3.x and above from the v7 release line, the checksums of the uploaded Wasm bytecodes are all stored under a single key. From ibc-go v8.0.x the checksums are stored using [`collections.KeySet`](/sdk/v0.53/build/packages/collections#keyset), whose full functionality became available in Cosmos SDK v0.50. There is therefore an [automatic migration handler](https://github.com/cosmos/ibc-go/blob/57fcdb9a9a9db9b206f7df2f955866dc4e10fef4/modules/light-clients/08-wasm/module.go#L115-L118) configured in the 08-wasm module to migrate the stored checksums to `collections.KeySet`. ## From v0.1.0+ibc-go-v8.0-wasmvm-v1.5 to v0.2.0-ibc-go-v8.3-wasmvm-v2.0 The `WasmEngine` interface has been updated to reflect changes in the function signatures of Wasm VM: ```diff expandable theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}} type WasmEngine interface { - StoreCode(code wasmvm.WasmCode) (wasmvm.Checksum, error) + StoreCode(code wasmvm.WasmCode, gasLimit uint64) (wasmvmtypes.Checksum, uint64, error) StoreCodeUnchecked(code wasmvm.WasmCode) (wasmvm.Checksum, error) Instantiate( checksum wasmvm.Checksum, env wasmvmtypes.Env, info wasmvmtypes.MessageInfo, initMsg []byte, store wasmvm.KVStore, goapi wasmvm.GoAPI, querier wasmvm.Querier, gasMeter wasmvm.GasMeter, gasLimit uint64, deserCost wasmvmtypes.UFraction, - ) (*wasmvmtypes.Response, uint64, error) + ) (*wasmvmtypes.ContractResult, uint64, error) Query( checksum wasmvm.Checksum, env wasmvmtypes.Env, queryMsg []byte, store wasmvm.KVStore, goapi wasmvm.GoAPI, querier wasmvm.Querier, gasMeter wasmvm.GasMeter, gasLimit uint64, deserCost wasmvmtypes.UFraction, - ) ([]byte, uint64, error) + ) (*wasmvmtypes.QueryResult, uint64, error) Migrate( checksum wasmvm.Checksum, env wasmvmtypes.Env, migrateMsg []byte, store wasmvm.KVStore, goapi wasmvm.GoAPI, querier wasmvm.Querier, gasMeter wasmvm.GasMeter, gasLimit uint64, deserCost wasmvmtypes.UFraction, - ) (*wasmvmtypes.Response, uint64, error) + ) (*wasmvmtypes.ContractResult, uint64, error) Sudo( checksum wasmvm.Checksum, env wasmvmtypes.Env, sudoMsg []byte, store wasmvm.KVStore, goapi wasmvm.GoAPI, querier wasmvm.Querier, gasMeter wasmvm.GasMeter, gasLimit uint64, deserCost wasmvmtypes.UFraction, - ) (*wasmvmtypes.Response, uint64, error) + ) (*wasmvmtypes.ContractResult, uint64, error) GetCode(checksum wasmvm.Checksum) (wasmvm.WasmCode, error) Pin(checksum wasmvm.Checksum) error Unpin(checksum wasmvm.Checksum) error } ``` Similar changes were required in the functions of `MockWasmEngine` interface. ### Chains The `SupportedCapabilities` field of `WasmConfig` is now of type `[]string`: ```diff theme={"theme":{"light":"github-light-high-contrast","dark":"github-dark-high-contrast"}} type WasmConfig struct { DataDir string - SupportedCapabilities string + SupportedCapabilities []string ContractDebugMode bool } ```