diff --git a/.azure-pipelines/main.yml b/.azure-pipelines/main.yml
index 0fcf260..c7fb965 100644
--- a/.azure-pipelines/main.yml
+++ b/.azure-pipelines/main.yml
@@ -70,7 +70,7 @@ pool:
 steps:
 - template: steps/setup-rust.yml
   parameters:
-    version: '1.45.0'
+    version: '1.56.0'
 - template: steps/-build.yml
 - template: steps/setup-emacs.yml
 - template: steps/-test.yml
diff --git a/CHANGELOG.md b/CHANGELOG.md
index d3fdcc9..35d57ce 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 - Upgraded to Rust 2021 edition.
+    - This also raised the minimum supported Rust version to 1.56.
 - Added support for Rust's non-zero integer types.
 
 ## [0.18.0] - 2021-09-26