diff --git a/extra/js78/PKGBUILD b/extra/js78/PKGBUILD
index d63c374d0..d8a19b124 100644
--- a/extra/js78/PKGBUILD
+++ b/extra/js78/PKGBUILD
@@ -5,7 +5,7 @@
 #  - patch to fix build on ARM
 
 pkgname=js78
-pkgver=78.3.1
+pkgver=78.4.0
 pkgrel=1
 pkgdesc="JavaScript interpreter and libraries - Version 78"
 arch=(x86_64)
@@ -17,7 +17,7 @@ checkdepends=(mercurial git)
 _relver=${pkgver}esr
 source=(https://archive.mozilla.org/pub/firefox/releases/$_relver/source/firefox-$_relver.source.tar.xz{,.asc}
         arm.patch)
-sha256sums=('5fd27d67689fe60803022035e556146d2dbce5e53d21c14d026fc31dd2e45be9'
+sha256sums=('8e3cf0bbf1062768134db2eb10ab774731ca5ec6694b65def82234bb0a9170fc'
             'SKIP'
             'bc00516032330760444939c516a60c78f868631e1b37f075f0fe71a53737b966')
 validpgpkeys=('14F26682D0916CDD81E37B6D61B7B526D98F0353') # Mozilla Software Releases <release@mozilla.com>