Oracle Names Server Version Banner

I was using Oracle 8.1.7.3 on AIX with Oracle Names Server.
After I upgrade it to 8.1.7.4, everything is working fine but the Oracle Names Server is still shown 8.1.7.3 as following:

Version banner is "Oracle Names for IBM/AIX RISC System/6000: Version 8.1.7.3.0 - Production"

I know it should be "8.1.7.4 - Prodution". I've checked that the Oracle patch is successfully installed. All other components are shown 8.1.7.4 except Oracle Names Server.

How could I work around?
Thanks.

Queyon