diff --git a/.circleci/config.yml b/.circleci/config.yml
index b42c313a..7b976b4f 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -51,7 +51,7 @@ jobs:
             - "/go/pkg/mod"
   rust:
     docker:
-      - image: rust:1.51.0
+      - image: rust:1.56.1
     working_directory: ~/proofs/rust
     steps:
       - checkout:
@@ -61,7 +61,7 @@ jobs:
           command: rustc --version; cargo --version; rustup --version
       - restore_cache:
           keys:
-            - v4-cargo-cache-rust:1.51.0-{{ arch }}-{{ checksum "Cargo.toml" }}
+            - v4-cargo-cache-rust:1.56.1-{{ arch }}-{{ checksum "Cargo.toml" }}
       - run:
           name: install protobuf dependencies
           command: |
@@ -91,14 +91,14 @@ jobs:
             - target/debug/.fingerprint
             - target/debug/build
             - target/debug/deps
-          key: v4-cargo-cache-rust:1.51.0-{{ arch }}-{{ checksum "Cargo.toml" }}
+          key: v4-cargo-cache-rust:1.56.1-{{ arch }}-{{ checksum "Cargo.toml" }}
       - run:
           name: Run all tests
           command: cargo test --all
 
   lint-rust:
     docker:
-      - image: rust:1.51.0
+      - image: rust:1.56.1
     working_directory: ~/proofs/rust
     steps:
       - checkout:
@@ -108,7 +108,7 @@ jobs:
           command: rustc --version; cargo --version; rustup --version; rustup target list --installed
       - restore_cache:
           keys:
-            - cargocache-v2-lint-rust:1.51.0-{{ checksum "Cargo.toml" }}
+            - cargocache-v2-lint-rust:1.56.1-{{ checksum "Cargo.toml" }}
       - run:
           name: Add rustfmt component
           command: rustup component add rustfmt
@@ -130,4 +130,4 @@ jobs:
             - target/debug/.fingerprint
             - target/debug/build
             - target/debug/deps
-          key: cargocache-v2-lint-rust:1.51.0-{{ checksum "Cargo.toml" }}
+          key: cargocache-v2-lint-rust:1.56.1-{{ checksum "Cargo.toml" }}
diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index 21021ea0..3cba61f4 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -2,11 +2,12 @@
 name = "ics23"
 version = "0.8.0-alpha"
 authors = ["Ethan Frey <ethanfrey@users.noreply.github.com>"]
-edition = "2018"
+edition = "2021"
 exclude = ["codegen"]
 description = "Merkle proof verification library - implements Cosmos ICS23 Spec"
 repository = "https://github.com/confio/ics23/tree/master/rust"
 license = "Apache-2.0"
+rust-version = "1.56.1"
 
 [workspace]
 members = ["codegen"]
diff --git a/rust/README.md b/rust/README.md
index 74469a58..2234c285 100644
--- a/rust/README.md
+++ b/rust/README.md
@@ -24,4 +24,4 @@ Unless you modify the protobuf file, you can ignore this step.
 
 ## MSRV
 
-The minimum supported Rust version (MSRV) is 1.51.0.
+The minimum supported Rust version (MSRV) is 1.56.1.
diff --git a/rust/src/lib.rs b/rust/src/lib.rs
index 05a7e23e..7b31a611 100644
--- a/rust/src/lib.rs
+++ b/rust/src/lib.rs
@@ -19,8 +19,8 @@ pub use api::{
 };
 pub use compress::{compress, decompress, is_compressed};
 pub use helpers::{Hash, Result};
-pub use verify::calculate_existence_root;
 pub use host_functions::HostFunctionsProvider;
+pub use verify::calculate_existence_root;
 
-#[cfg(feature  ="std")]
+#[cfg(feature = "std")]
 pub use host_functions::host_functions_impl::HostFunctionsManager;
diff --git a/rust/src/ops.rs b/rust/src/ops.rs
index 7574803f..60acf993 100644
--- a/rust/src/ops.rs
+++ b/rust/src/ops.rs
@@ -40,12 +40,12 @@ fn prepare_leaf_data<H: HostFunctionsProvider>(
 fn do_hash<H: HostFunctionsProvider>(hash: HashOp, data: &[u8]) -> Hash {
     match hash {
         HashOp::NoHash => Hash::from(data),
-        HashOp::Sha256 => Hash::from(H::sha2_256(data).as_slice()),
-        HashOp::Sha512 => Hash::from(H::sha2_512(data).as_slice()),
-        HashOp::Keccak => Hash::from(H::sha3_512(data).as_slice()),
-        HashOp::Ripemd160 => Hash::from(H::ripemd160(data).as_slice()),
-        HashOp::Bitcoin => Hash::from(H::ripemd160(H::sha2_256(data).as_slice()).as_slice()),
-        HashOp::Sha512256 => Hash::from(H::sha2_512_truncated(data).as_slice()),
+        HashOp::Sha256 => Hash::from(H::sha2_256(data)),
+        HashOp::Sha512 => Hash::from(H::sha2_512(data)),
+        HashOp::Keccak => Hash::from(H::sha3_512(data)),
+        HashOp::Ripemd160 => Hash::from(H::ripemd160(data)),
+        HashOp::Bitcoin => Hash::from(H::ripemd160(&H::sha2_256(data)[..])),
+        HashOp::Sha512256 => Hash::from(H::sha2_512_truncated(data)),
     }
 }
 
@@ -81,6 +81,7 @@ fn proto_len(length: usize) -> Result<Hash> {
 mod tests {
     use super::*;
     use crate::host_functions::host_functions_impl::HostFunctionsManager;
+    use sp_std::vec;
     use sp_std::vec::Vec;
 
     fn decode(input: &str) -> Vec<u8> {