diff --git a/mingw-w64-emscripten/PKGBUILD b/mingw-w64-emscripten/PKGBUILD
index 8503bc91aa..cb918bf548 100644
--- a/mingw-w64-emscripten/PKGBUILD
+++ b/mingw-w64-emscripten/PKGBUILD
@@ -6,10 +6,10 @@ pkgname=("${MINGW_PACKAGE_PREFIX}-${_realname}")
 # Sadly, upstream currently suggests bundling a binaryen version for the time being:
 # https://github.com/emscripten-core/emscripten/issues/12252
 # I'm obviously unhappy about that but it appears to be the only practical solution for the time being.
-pkgver=4.0.20
+pkgver=4.0.21
 # NOTE: You need to run ./get-compatible-versions.sh after changing the pkgver!
-_binaryen_revision=6d5fed324a603d7f8c9f1800a03043fb62abc7d2
-_llvm_project_revision=7693f124ff7fbeacce66ef3012fef119b40db330
+_binaryen_revision=5efa50595eb36a46aff9e15151a25d858ca0acf0
+_llvm_project_revision=d20d84fec5945fcc16aa6f63879e1458d4af9ea6
 pkgrel=1
 pkgdesc="Compile C and C++ into highly-optimizable JavaScript for the web (mingw-w64)"
 arch=('any')
@@ -35,9 +35,9 @@ install="emscripten-${MSYSTEM}.install"
 source=("git+$msys2_repository_url#tag=$pkgver"
         "llvm-project-$_llvm_project_revision.tar.gz::https://github.com/llvm/llvm-project/archive/$_llvm_project_revision.tar.gz"
         "binaryen-$_binaryen_revision.tar.gz::https://github.com/WebAssembly/binaryen/archive/$_binaryen_revision.tar.gz")
-sha256sums=('cf7a8d355da542c54e7824d3419872a4a35fdb95aa7242ba7b665ec584036ec1'
-            '16a2babc79137037b6d8c6ac5add9ddead664b0f169163d3dffcc0108d6a9e6f'
-            '72225f5579554dc866761b243fd4a363cf193155b1fdaab37cba77f9eafd76d0')
+sha256sums=('a89dbe97f1760adb7b98fa42c51a7518bb410f45e9920240dd04dba4929c7062'
+            '3a946ae7bfe1c820bc9bf8e693ce3d6379eb921933d0612cb365af673df98bca'
+            '9182edd2a63ab307b8016571d77c4f29f61bf381fa3183105c17bf315db6ed91')
 noextract=("llvm-project-$_llvm_project_revision.tar.gz")
 
 prepare() {