When you convert a database server, several modifications make the format of the databases incompatible with the older version. The onmode -b command restores the databases to a format that is compatible with the earlier version. You must revert the databases before users can access the data with the earlier database server version. The utility does not revert changes made to the layout of the data that do not affect compatibility.
You must be user root or user informix to execute onmode.
You must be a member of the Informix-Admin group to execute onmode.