diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f91a561253b..9b9a4ac5819 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -101,7 +101,7 @@ jobs:
   compatibility-test:
     strategy:
       matrix:
-        go-version: ["1.23.0", "~1.22.4", "~1.21.12"]
+        go-version: ["1.23.0", "~1.22.4"]
         platform:
           - os: ubuntu-latest
             arch: "386"
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 803c7d70cca..92f46e4a937 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ## [Unreleased]
 
+### Removed
+
+- Drop support for [Go 1.21]. (#6046)
+
 <!-- Released section -->
 <!-- Don't change this section unless doing release -->
 
diff --git a/README.md b/README.md
index a16558905b5..eb4b6e19889 100644
--- a/README.md
+++ b/README.md
@@ -52,22 +52,16 @@ This project is tested on the following systems.
 | -------- | ---------- | ------------ |
 | Ubuntu   | 1.23       | amd64        |
 | Ubuntu   | 1.22       | amd64        |
-| Ubuntu   | 1.21       | amd64        |
 | Ubuntu   | 1.23       | 386          |
 | Ubuntu   | 1.22       | 386          |
-| Ubuntu   | 1.21       | 386          |
 | macOS 13 | 1.23       | amd64        |
 | macOS 13 | 1.22       | amd64        |
-| macOS 13 | 1.21       | amd64        |
 | macOS    | 1.23       | arm64        |
 | macOS    | 1.22       | arm64        |
-| macOS    | 1.21       | arm64        |
 | Windows  | 1.23       | amd64        |
 | Windows  | 1.22       | amd64        |
-| Windows  | 1.21       | amd64        |
 | Windows  | 1.23       | 386          |
 | Windows  | 1.22       | 386          |
-| Windows  | 1.21       | 386          |
 
 While this project should work for other systems, no compatibility guarantees
 are made for those systems currently.