diff --git a/conf/app.src b/conf/app.src
index 3c6c530..61b5b8c 100644
--- a/conf/app.src
+++ b/conf/app.src
@@ -1,5 +1,5 @@
-SOURCE_URL=https://github.com/BookStackApp/BookStack/archive/refs/tags/v21.12.3.tar.gz
-SOURCE_SUM=c6182009052069b62e1c70307bc030cc22439ef1da29baf6a315690093693557
+SOURCE_URL=https://github.com/BookStackApp/BookStack/archive/refs/tags/v21.12.4.tar.gz
+SOURCE_SUM=3af6ee1dbcdcd519dc2e42b277c845678162154f7f15d37457d62e6e8f7eea5a
 SOURCE_SUM_PRG=sha256sum
 SOURCE_FORMAT=tar.gz
 SOURCE_IN_SUBDIR=true