The $INCLUDE directive

If any of your zone files include other files with the $INCLUDE directive, the installer will not notice. If they are located inside the data directory, as specified in the directory statement, you must manually copy them from the old data directory to the new one after installation. The old data directory is in the same place as before, but its name has had ".bak" appended. For example, if your directory statement specifies /var/named, your old data directory will be /var/named.bak.

If any included file is specified with just its name, rather than some kind of path to a subdirectory, be sure to put it directly into your data directory. Do not put the included file into the same location as the zone files; included files are looked for (if no path is specified) in the root of the data directory, but the installer places master zone files into the hosts/masters subdirectory.