apache2 patch

hello all I updated apache2 through YOU. I noticed that nearly no file has been changed except httpd2-prefork I have chrooted apache2 so every time that a apache2-patch comes to surface i check the apache2*.rpm for recent chagnes (in bytes, timestamp) and then copy it to the chrooted area. I noticed that /usr/sbin/httpd2-prefork has new timestamp (22/jul) but the same size (in bytes) with the older one. Can anyone explain to me what does this mean? How the patch has fit in that binary and the size remains the same? Thanks in advance John