diff --git a/.gitignore b/.gitignore
index 771d696..c0922ac 100644
--- a/.gitignore
+++ b/.gitignore
@@ -26,3 +26,4 @@ bugzilla-3.6.1.tar.gz
 /bugzilla-4.4.11.tar.gz
 /bugzilla-5.0.2.tar.gz
 /bugzilla-5.0.3.tar.gz
+/bugzilla-5.0.4.tar.gz
diff --git a/bugzilla-1438957-concatenate-assets.patch b/bugzilla-1438957-concatenate-assets.patch
new file mode 100644
index 0000000..a678976
--- /dev/null
+++ b/bugzilla-1438957-concatenate-assets.patch
@@ -0,0 +1,12 @@
+diff -up ./Bugzilla/Constants.pm.orig ./Bugzilla/Constants.pm
+--- ./Bugzilla/Constants.pm.orig	2018-02-18 12:22:45.541837039 +0100
++++ ./Bugzilla/Constants.pm	2018-02-18 12:22:53.538784733 +0100
+@@ -213,7 +213,7 @@ use constant LOCAL_FILE  => 'bugzilla-up
+ # When true CSS and JavaScript assets will be concatanted and minified at
+ # run-time, to reduce the number of requests required to render a page.
+ # Setting this to a false value can help debugging.
+-use constant CONCATENATE_ASSETS => 1;
++use constant CONCATENATE_ASSETS => 0;
+ 
+ # These are unique values that are unlikely to match a string or a number,
+ # to be used in criteria for match() functions and other things. They start
diff --git a/bugzilla.spec b/bugzilla.spec
index cc2edd3..1cb5851 100644
--- a/bugzilla.spec
+++ b/bugzilla.spec
@@ -4,8 +4,8 @@
 Summary: Bug tracking system
 URL: https://www.bugzilla.org/
 Name: bugzilla
-Version: 5.0.3
-Release: 10%{?dist}
+Version: 5.0.4
+Release: 1%{?dist}
 License: MPLv1.1
 Source0: https://ftp.mozilla.org/pub/mozilla.org/webtools/bugzilla-%{version}.tar.gz
 Source1: bugzilla-httpd-conf
@@ -13,7 +13,7 @@ Source2: README.fedora.bugzilla
 Source3: bugzilla.cron-daily
 Patch0: bugzilla-rw-paths.patch
 Patch1: bugzilla-dnf.patch
-Patch2: bugzilla-1301887-File-Slurp-Warnings.patch
+Patch2: bugzilla-1438957-concatenate-assets.patch
 
 BuildArch: noarch
 Requires: patchutils
@@ -71,6 +71,7 @@ Group: Applications/Publishing
 Summary: Bugzilla contributed scripts
 Group: Applications/Publishing
 BuildRequires: python2
+BuildRequires: python2-rpm-macros
 
 %{?perl_default_filter}
 
@@ -177,9 +178,8 @@ rm -rf lib/CGI*
 rm -f js/yui/*/*.swf
 
 # Deal with changing /usr/local paths here instead of via patches
-%{__perl} -pi -e 's|/usr/local/bin/python\b|%{__python}|' contrib/*.py
-%{__perl} -pi -e 's|/usr/local/bin/ruby\b|%{_bindir}/ruby|' contrib/*.rb
-%{__perl} -pi -e 's|/usr/bin/env python|%{__python}|' contrib/bugzilla-submit/bugzilla-submit
+%{__perl} -pi -e 's|/usr/local/bin/python\b|%{__python2}|' contrib/*.py
+%{__perl} -pi -e 's|/usr/bin/env python|%{__python2}|' contrib/bugzilla-submit/bugzilla-submit
 
 grep -rl '/usr/lib/sendmail\b' contrib docs \
 | xargs %{__perl} -pi -e 's|/usr/lib/sendmail\b|%{_sbindir}/sendmail|'
@@ -291,6 +291,12 @@ popd > /dev/null)
 %{bzinstallprefix}/bugzilla/contrib/Bugzilla.pm
 
 %changelog
+* Sun Feb 18 2018 Emmanuel Seyman <emmanuel@seyman.fr> - 5.0.4-1
+- Update to 5.0.4
+- Remove backported File::Slurp patch, no longer needed
+- use %%{__python2} instead of %%{__python}
+- Disable the concatenation of assets (#1438957)
+
 * Wed Feb 07 2018 Iryna Shcherbina <ishcherb@redhat.com> - 5.0.3-10
 - Update Python 2 dependency declarations to new packaging standards
   (See https://fedoraproject.org/wiki/FinalizingFedoraSwitchtoPython3)
diff --git a/sources b/sources
index e160adf..6ed1eab 100644
--- a/sources
+++ b/sources
@@ -1 +1 @@
-b78365742a85cd030c87af12c196e8e9  bugzilla-5.0.3.tar.gz
+SHA512 (bugzilla-5.0.4.tar.gz) = 9a508c623406fe71c485f85091c0dec87f7f600190bb88e6b097afaeb94a0bfc32db664609debb2265f21f48734bd040e2f5ecbf40dba0071940f31e195c8dbc