diff --git a/ChangeLog b/ChangeLog
index b9b940ce8..535ee055b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2001-01-31  Richard Frith-Macdonald <rfm@gnu.org>
+
+	* Source/NSDate.m: pass dates over DO bycopy unless explicitly byref.
+	* Source/NSTimeZone.m: pass time zones over DO bycopy unless
+	explicitly byref.
+
 2001-01-30  Michael Hanni  <mhanni@sprintmail.com>
 
 	* Source/.cvsignore: tweaked to cover a few more items.
diff --git a/Source/NSDate.m b/Source/NSDate.m
index 89938ec0f..a98eaae4f 100644
--- a/Source/NSDate.m
+++ b/Source/NSDate.m
@@ -34,6 +34,7 @@
 #include <Foundation/NSCharacterSet.h>
 #include <Foundation/NSScanner.h>
 #include <Foundation/NSObjCRuntime.h>
+#include <Foundation/NSPortCoder.h>
 #include <base/preface.h>
 #include <base/behavior.h>
 #if HAVE_SYS_TIME_H
@@ -880,11 +881,11 @@ GSTimeNow()
   return abstractClass;
 }
 
-- (id) replacementObjectForPortCoder: (NSPortCoder*)aRmc
+- (id) replacementObjectForPortCoder: (NSPortCoder*)aCoder
 {
-  /* Make sure that Connection's always send us bycopy,
-     i.e. as our own class, not a Proxy class. */
-  return self;
+  if ([aCoder isByref] == NO)
+    return self;
+  return [super replacementObjectForPortCoder: aCoder];
 }
 
 - (void) encodeWithCoder: (NSCoder*)coder
diff --git a/Source/NSTimeZone.m b/Source/NSTimeZone.m
index 27c00562f..e25edb13b 100644
--- a/Source/NSTimeZone.m
+++ b/Source/NSTimeZone.m
@@ -63,6 +63,7 @@
 #include <Foundation/NSMapTable.h>
 #include <Foundation/NSThread.h>
 #include <Foundation/NSNotification.h>
+#include <Foundation/NSPortCoder.h>
 
 #define NOID
 #include "tzfile.h"
@@ -1109,6 +1110,13 @@ static NSMapTable	*absolutes = 0;
   return [self subclassResponsibility: _cmd];
 }
 
+- (id) replacementObjectForPortCoder: (NSPortCoder*)aCoder
+{
+  if ([aCoder isByref] == NO)
+    return self;
+  return [super replacementObjectForPortCoder: aCoder];
+}
+
 - (int) secondsFromGMT
 {
   return [self secondsFromGMTForDate: [NSDate date]];