diff --git a/mozilla/config/Makefile.in b/mozilla/config/Makefile.in
index 37a715be4df..c520df475d2 100644
--- a/mozilla/config/Makefile.in
+++ b/mozilla/config/Makefile.in
@@ -141,7 +141,7 @@ build_number: FORCE
 
 nsBuildID.h: nsBuildID.h.in build_number 
 	$(RM) $@
-	$(PERL) -I$(srcdir) $(srcdir)/aboutime.pl $@ build_number $(srcdir)/nsBuildID.h.in
+	$(PERL) -I$(srcdir) $(srcdir)/aboutime.pl -m $(srcdir)/milestone.txt $@ build_number $(srcdir)/nsBuildID.h.in
 
 ifndef CROSS_COMPILE
 ifdef USE_ELF_DYNSTR_GC
diff --git a/mozilla/config/aboutime.pl b/mozilla/config/aboutime.pl
index 4d35ec56105..cdf59a55c76 100755
--- a/mozilla/config/aboutime.pl
+++ b/mozilla/config/aboutime.pl
@@ -1,12 +1,24 @@
 
 use strict;
-use mozBDate;
+use Getopt::Std;
+require mozBDate;
+require "Moz/Milestone.pm";
+
+my $mfile;
+getopts('m:');
+if (defined($::opt_m)) {
+    $mfile = $::opt_m;
+}
 
 my $outfile = $ARGV[0];
 my $build_num_file = $ARGV[1];
 my $infile = "";
 
 $infile = $ARGV[2] if ("$ARGV[2]" ne "");
-    
+
+if (defined($mfile)) {
+    my $milestone = &Moz::Milestone::getOfficialMilestone($mfile);
+    &mozBDate::SetMilestone($milestone);
+}
 &mozBDate::SubstituteBuildNumber($outfile, $build_num_file, $infile);
 
diff --git a/mozilla/config/mozBDate.pm b/mozilla/config/mozBDate.pm
index 1b367e16738..56d7f3b3e0b 100755
--- a/mozilla/config/mozBDate.pm
+++ b/mozilla/config/mozBDate.pm
@@ -26,15 +26,17 @@ use IO::File;
 
 BEGIN {
     use Exporter ();
-    use vars qw ($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS);
+    use vars qw ($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS $milestone);
 
     $VERSION = 1.00;
     @ISA = qw(Exporter);
-    @EXPORT = qw(&UpdateBuildNumber &SubstituteBuildNumber);
+    @EXPORT = qw(&UpdateBuildNumber &SubstituteBuildNumber &SetMilestone);
     %EXPORT_TAGS = ( );
     @EXPORT_OK = qw();
 }
 
+local $mozBDate::milestone = "0.0";
+
 sub write_number($) {
     my ($file, $num) = @_;
     unlink($file);
@@ -95,7 +97,7 @@ sub SubstituteBuildNumber($$$) {
     my ($outfile, $build_num, $infile) = @_;
     my $INFILE = new IO::File;
     my $OUTFILE = new IO::File;
-    
+
     open $INFILE, "<$build_num";
     my $build = <$INFILE>;
     close $INFILE;
@@ -122,6 +124,15 @@ sub SubstituteBuildNumber($$$) {
         $id =~ s/NS_BUILD_ID\s\d+/$temp/;
         print $OUTFILE $id;
     }
+    elsif ($id =~ "GRE_BUILD_ID") {
+	if (defined($ENV{'MOZ_MILESTONE_RELEASE'})) {
+	    $temp = "GRE_BUILD_ID " . $milestone;
+	} else {
+	    $temp = "GRE_BUILD_ID " . "${milestone}_${build}";
+	}
+        $id =~ s/GRE_BUILD_ID\s\d+/$temp/;
+        print $OUTFILE $id;
+    }
     else {
         print $OUTFILE $_;
     }
@@ -134,6 +145,11 @@ sub SubstituteBuildNumber($$$) {
     rename "${outfile}.old", "$outfile";
 }
 
+sub SetMilestone($) {
+    my ($mstone) = (@_);
+    $milestone = $mstone if ($mstone ne "");
+}
+
 END {};
 
 1;
diff --git a/mozilla/config/nsBuildID.h.in b/mozilla/config/nsBuildID.h.in
index ff62fc8c3ca..afde5e17b42 100644
--- a/mozilla/config/nsBuildID.h.in
+++ b/mozilla/config/nsBuildID.h.in
@@ -9,5 +9,15 @@
 */
 #define NS_BUILD_ID 0000000000
 
+/* GRE_BUILD_ID - GRE build version identifier
+ *
+ * If creating a release build (eg, MOZILLA_OFFICIAL is set), then 
+ * GRE_BUILD_ID will be updated to contain <milestone>_<build id>.  
+ * If building a milestone build (eg, MOZ_MILESTONE_RELEASE is set), then 
+ * GRE_BUILD_ID will just contain <milestone>. 
+ *
+ */
+#define GRE_BUILD_ID 00000000000
+
 #endif /* _NSBUILDID_H_ */