diff --git a/.gitignore b/.gitignore
index 43e2bdd..1296fff 100644
--- a/.gitignore
+++ b/.gitignore
@@ -317,3 +317,5 @@ firefox-3.6.4.source.tar.bz2
 /cbindgen-vendor.tar.xz
 /firefox-langpacks-63.0.1-20181101.tar.xz
 /firefox-63.0.1.source.tar.xz
+/firefox-63.0.3.source.tar.xz
+/firefox-langpacks-63.0.3-20181115.tar.xz
diff --git a/firefox-locale-debug.patch b/firefox-locale-debug.patch
new file mode 100644
index 0000000..0a481cb
--- /dev/null
+++ b/firefox-locale-debug.patch
@@ -0,0 +1,11 @@
+diff -up firefox-63.0.1/intl/locale/LocaleService.cpp.old firefox-63.0.1/intl/locale/LocaleService.cpp
+--- firefox-63.0.1/intl/locale/LocaleService.cpp.old	2018-11-14 13:34:16.338285161 +0100
++++ firefox-63.0.1/intl/locale/LocaleService.cpp	2018-11-14 13:34:21.438270308 +0100
+@@ -708,7 +708,6 @@ LocaleService::GetDefaultLocale(nsACStri
+     GetGREFileContents("update.locale", &locale);
+     locale.Trim(" \t\n\r");
+     // This should never be empty.
+-    MOZ_ASSERT(!locale.IsEmpty());
+     if (SanitizeForBCP47(locale, true)) {
+       mDefaultLocale.Assign(locale);
+     }
diff --git a/firefox.spec b/firefox.spec
index 588844d..61dc7f0 100644
--- a/firefox.spec
+++ b/firefox.spec
@@ -87,13 +87,13 @@
 
 Summary:        Mozilla Firefox Web browser
 Name:           firefox
-Version:        63.0.1
-Release:        6%{?pre_tag}%{?dist}
+Version:        63.0.3
+Release:        1%{?pre_tag}%{?dist}
 URL:            https://www.mozilla.org/firefox/
 License:        MPLv1.1 or GPLv2+ or LGPLv2+
 Source0:        https://archive.mozilla.org/pub/firefox/releases/%{version}%{?pre_version}/source/firefox-%{version}%{?pre_version}.source.tar.xz
 %if %{with langpacks}
-Source1:        firefox-langpacks-%{version}%{?pre_version}-20181101.tar.xz
+Source1:        firefox-langpacks-%{version}%{?pre_version}-20181115.tar.xz
 %endif
 Source2:        cbindgen-vendor.tar.xz
 Source10:       firefox-mozconfig
@@ -137,6 +137,7 @@ Patch221:        firefox-fedora-ua.patch
 Patch224:        mozilla-1170092.patch
 #ARM run-time patch
 Patch226:        rhbz-1354671.patch
+Patch227:        firefox-locale-debug.patch
 
 # Upstream patches
 Patch402:        mozilla-1196777.patch
@@ -353,6 +354,7 @@ This package contains results of tests executed during build.
 %ifarch aarch64
 %patch226 -p1 -b .1354671
 %endif
+%patch227 -p1 -b .locale-debug
 
 %patch402 -p1 -b .1196777
 %patch406 -p1 -b .256180
@@ -930,6 +932,9 @@ gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :
 #---------------------------------------------------------------------
 
 %changelog
+* Thu Nov 15 2018 Martin Stransky <stransky@redhat.com> - 63.0.3-1
+- Updated to latest upstream (63.0.3)
+
 * Tue Nov 13 2018 Martin Stransky <stransky@redhat.com> - 63.0.1-6
 - Added an option to build with clang/llvm.
 - Fixed debug builds.
diff --git a/sources b/sources
index a44200d..fdac8ed 100644
--- a/sources
+++ b/sources
@@ -1,3 +1,3 @@
 SHA512 (cbindgen-vendor.tar.xz) = 6d1a6ef48e77920bccd51af27c836d66aed49a571a0f5298df9cc87724467a5542e382485aa6c5ed2b516277086ffe4d5360b9eb4c0ab62ef6e3e027fc736ead
-SHA512 (firefox-langpacks-63.0.1-20181101.tar.xz) = 7f197e5df57f9287bcdaf014049244fec8989f563899eeb29501a073321e7d55910020e426722be9d91865f20690ab0ea74b5518a2bcbc47d63b3e1eeaa601ce
-SHA512 (firefox-63.0.1.source.tar.xz) = 29acad70259d71a924cbaf4c2f01fb034cf8090759b3a2d74a5eabc2823f83b6508434e619d8501d3930702e2bbad373581a70e2ce57aead9af77fc42766fbe2
+SHA512 (firefox-63.0.3.source.tar.xz) = 6c05aea0b704ede39abf83aba02c4713a8f5ab6673a8897f6bb4147d5e90c234e351f584010e195e46382d217d02d8eec5a5d4b9f4694c14c55172987bb695c2
+SHA512 (firefox-langpacks-63.0.3-20181115.tar.xz) = d6e35d0924ff49ad8fdd894c079833e72c3e264d3a1e6d7a54028f8e931c3ec5250e08d388ac8ca46f6c2ab448e89b0c266d1630f8778ff8834122711057d890