diff --git a/CHANGELOG.md b/CHANGELOG.md
index 513329e7..08fc72b3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,11 @@ Rhai Release Notes
 Version 1.6.0
 =============
 
+Compiler version
+----------------
+
+* Minimum compiler version is now `1.57` due to [`smartstring`](https://crates.io/crates/smartstring) dependency.
+
 Bug fixes
 ---------
 
diff --git a/Cargo.toml b/Cargo.toml
index 027d135f..4cc1409d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,6 +4,7 @@ members = [".", "codegen"]
 [package]
 name = "rhai"
 version = "1.6.0"
+rust-version = "1.57"
 edition = "2018"
 authors = ["Jonathan Turner", "Lukáš Hozda", "Stephen Chung", "jhwgh1968"]
 description = "Embedded scripting for Rust"
diff --git a/README.md b/README.md
index f64d937b..cf33fd5d 100644
--- a/README.md
+++ b/README.md
@@ -26,7 +26,7 @@ Targets and builds
 * All CPU and O/S targets supported by Rust, including:
   * WebAssembly (WASM)
   * `no-std`
-* Minimum Rust version 1.51
+* Minimum Rust version 1.57
 
 
 Standard features