diff --git a/checkin_notes b/checkin_notes
index 4aa0e4d172..5b2b4cb4ec 100755
--- a/checkin_notes
+++ b/checkin_notes
@@ -3547,3 +3547,31 @@ Bruce 16 April 2007
         server_types.h
     doc/
         sched_locality.php
+
+Charlie 16 Apr 2007
+    - Mac: Update backtrace to use entirely new code from Apple Developer 
+        Technical Support.  The format is now compatible with OS X's 
+        built-in Crash Reporter, and is ready for 64-bit Mac Intel 
+        applications (which will be available in OS 10.5).  If the backtrace 
+        is from a stripped application, the output of this new code can be 
+        run through a new shell script (available on Apple's web site) to 
+        add symbols to it from a separate symbol file - this is a very useful 
+        feature.  For details, see comments in mac_backtrace.h.
+        
+        Note: We build the PowerPC applications with GCC-3.3 to be backward 
+        compatible with OS 10.3.0 - 10.3.8, and GCC 3.3 does not support 
+        64-bit applications, and Apple discontinued production of PowerPC 
+        Macs in 2006, so this backtrace code does not support 64-bit PowerPC 
+        G5 applications.
+        
+    lib/
+        mac_backtrace.C,h (removed)
+        mac/
+            dyld_gdb.h (added)
+            mac_backtrace.C,h (added)
+            QBacktrace.c,h (added)
+            QCrashReport.c,h (added)
+            QMachOImage.c,h (added)
+            QMachOImageList.c,h (added)
+            QSymbols.c,h (added)
+            QTaskMemory.c,h (added)