diff --git a/conf/app.src b/conf/app.src
index 80e3149..d0be75e 100644
--- a/conf/app.src
+++ b/conf/app.src
@@ -1,5 +1,5 @@
-SOURCE_URL=https://github.com/backdrop/backdrop/releases/download/1.21.3/backdrop.zip
-SOURCE_SUM=3088dbc7e683c80a581a6feae4a54932fe2bf9eab2e93d5f79f4bf430d87df15
+SOURCE_URL=https://github.com/backdrop/backdrop/releases/download/1.21.4/backdrop.zip
+SOURCE_SUM=1f79f016ea72af5ccff50a1c2d9f86f113049e039f89187ba87c1df5f572c164
 SOURCE_SUM_PRG=sha256sum
 SOURCE_FORMAT=zip
 SOURCE_IN_SUBDIR=true
diff --git a/manifest.json b/manifest.json
index 7b727ee..7cbb74e 100644
--- a/manifest.json
+++ b/manifest.json
@@ -6,7 +6,7 @@
         "en": "Easy-to-use CMS for building professional websites",
         "fr": "CMS facile à utiliser pour créer des sites Web professionnels"
     },
-    "version": "1.21.3~ynh1",
+    "version": "1.21.4~ynh1",
     "url": "https://backdropcms.org/",
     "upstream": {
         "license": "GPL-2.0",