diff --git a/extra/js91/PKGBUILD b/extra/js91/PKGBUILD
index 5ddc9f542..af4f7577e 100644
--- a/extra/js91/PKGBUILD
+++ b/extra/js91/PKGBUILD
@@ -4,19 +4,19 @@
 #  - configure with --disable-lto, --disable-rust-simd
 
 pkgname=js91
-pkgver=91.12.0
+pkgver=91.13.0
 pkgrel=1
 pkgdesc="JavaScript interpreter and libraries - Version 91"
 arch=(x86_64)
 url="https://spidermonkey.dev/"
 license=(MPL)
 depends=(gcc-libs readline zlib sh)
-makedepends=(zip autoconf2.13 python-setuptools python-psutil rust llvm clang lld)
+makedepends=(zip autoconf2.13 python-setuptools python-psutil rustup llvm clang lld)
 checkdepends=(mercurial git)
 options=(!lto debug)
 _relver=${pkgver}esr
 source=(https://archive.mozilla.org/pub/firefox/releases/$_relver/source/firefox-$_relver.source.tar.xz{,.asc})
-sha256sums=('6c0b8ff1826885eeace19ec87ae9e5a6512284d4863930713c8a288a03832b5c'
+sha256sums=('53be2bcde0b5ee3ec106bd8ba06b8ae95e7d489c484e881dfbe5360e4c920762'
             'SKIP')
 validpgpkeys=('14F26682D0916CDD81E37B6D61B7B526D98F0353') # Mozilla Software Releases <release@mozilla.com>
 
@@ -24,6 +24,10 @@ validpgpkeys=('14F26682D0916CDD81E37B6D61B7B526D98F0353') # Mozilla Software Rel
 COMPRESSZST+=(--long)
 
 prepare() {
+  # packed_simd no longer builds with 1.63.0
+  rustup toolchain update --profile minimal 1.62.1
+  rustup default 1.62.1
+
   mkdir mozbuild
   cd firefox-$pkgver