diff --git a/CHANGELOG.md b/CHANGELOG.md
index cfbb84611..2a9ba1ba7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@ Note: In this file, do not use the hard wrap in the middle of a sentence for com
 
 ## [Unreleased]
 
+- Update `just@latest` to 1.21.0.
+
 ## [2.23.6] - 2023-12-29
 
 - Update `just@latest` to 1.20.0.
diff --git a/manifests/just.json b/manifests/just.json
index a4a570d2e..5defca3f6 100644
--- a/manifests/just.json
+++ b/manifests/just.json
@@ -18,10 +18,30 @@
     }
   },
   "latest": {
-    "version": "1.20.0"
+    "version": "1.21.0"
   },
   "1": {
-    "version": "1.20.0"
+    "version": "1.21.0"
+  },
+  "1.21": {
+    "version": "1.21.0"
+  },
+  "1.21.0": {
+    "x86_64_linux_musl": {
+      "checksum": "3292fd257f2e2dfd4cb0d5650aa5e47d2c99cee1233446378eb45a7b045f3b30"
+    },
+    "x86_64_macos": {
+      "checksum": "f547f5d256782b946b22fa73e0d7fdd4e7d733c637480d4c4d6fd2feca046a59"
+    },
+    "x86_64_windows": {
+      "checksum": "54fc05c55b84ea1a7a80acf8450d13ba06472ecdd4ca341817ba45a6780c8f4a"
+    },
+    "aarch64_linux_musl": {
+      "checksum": "2224bd7232f86db42a41411493c7806ae5938ad5ef3cfd37af064ed90d6688d2"
+    },
+    "aarch64_macos": {
+      "checksum": "adab0bb1707df8d4995c103a87451e00b37936550fbf1586f00a38328eb6ef48"
+    }
   },
   "1.20": {
     "version": "1.20.0"