diff --git a/pkgs/applications/networking/browsers/firefox/common.nix b/pkgs/applications/networking/browsers/firefox/common.nix
index b3719e841e5..933d16c027e 100644
--- a/pkgs/applications/networking/browsers/firefox/common.nix
+++ b/pkgs/applications/networking/browsers/firefox/common.nix
@@ -87,6 +87,11 @@ stdenv.mkDerivation rec {
 
   inherit src unpackPhase patches meta;
 
+  # Ignore trivial whitespace changes in patches, this fixes compatibility of
+  # ./env_var_for_system_dir.patch with Firefox >=65 without having to track
+  # two patches.
+  patchFlags = [ "-p1" "-l" ];
+
   buildInputs = [
     gtk2 perl zip libIDL libjpeg zlib bzip2
     dbus dbus-glib pango freetype fontconfig xorg.libXi xorg.libXcursor
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 9621ca428aa..e407c9dc44e 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -17130,7 +17130,7 @@ in
       libpng = libpng_apng;
       python = python2;
       gnused = gnused_422;
-      icu = icu59;
+      icu = icu63;
       inherit (darwin.apple_sdk.frameworks) CoreMedia ExceptionHandling
                                             Kerberos AVFoundation MediaToolbox
                                             CoreLocation Foundation AddressBook;