diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 05384a2..81c331f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -16,7 +16,7 @@ jobs:
       matrix:
         toolchain:
           - stable
-          - 1.67.0 # MSRV
+          - 1.70.0 # MSRV
     steps:
       - uses: actions/checkout@v1
       - uses: dtolnay/rust-toolchain@master
@@ -34,7 +34,7 @@ jobs:
       matrix:
         toolchain:
           - stable
-          - 1.67.0 # MSRV
+          - 1.70.0 # MSRV
     steps:
       - uses: actions/checkout@v1
       - uses: dtolnay/rust-toolchain@master
diff --git a/Cargo.toml b/Cargo.toml
index e04dabf..ac25269 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "yubihsm"
-version = "0.42.1"
+version = "0.43.0-pre"
 description = """
 Pure Rust client for YubiHSM2 devices with support for HTTP and
 USB-based access to the device. Supports most HSM functionality
@@ -14,7 +14,7 @@ readme = "README.md"
 categories = ["cryptography", "hardware-support"]
 keywords = ["ecdsa", "ed25519", "hmac", "hsm", "yubikey"]
 edition = "2021"
-rust-version = "1.67"
+rust-version = "1.70"
 
 [dependencies]
 aes = { version = "0.8", features = ["zeroize"] }
diff --git a/README.md b/README.md
index d772bf0..5f505ca 100644
--- a/README.md
+++ b/README.md
@@ -30,7 +30,7 @@ or endorsed by Yubico (although whoever runs their Twitter account
 
 ## Minimum Supported Rust Version
 
-This crate requires Rust **1.57** or newer.
+This crate requires Rust **1.70** or newer.
 
 ## Supported Commands
 
@@ -159,7 +159,7 @@ See [LICENSE-APACHE](LICENSE-APACHE) and [LICENSE-MIT](LICENSE-MIT) for details.
 [deps-image]: https://deps.rs/repo/github/iqlusioninc/yubihsm.rs/status.svg
 [deps-link]: https://deps.rs/repo/github/iqlusioninc/yubihsm.rs
 [license-image]: https://img.shields.io/badge/license-Apache2.0/MIT-blue.svg
-[rustc-image]: https://img.shields.io/badge/rustc-1.67+-blue.svg
+[rustc-image]: https://img.shields.io/badge/rustc-1.70+-blue.svg
 
 [//]: # (general links)