HACMP 5.4.1 requires the base level 5.4.0 either to be in the same installation repository or to be installed on the target machine(s).  It can't be installed without 5.4.0.

There won't be any new fixes for HACMP 5.4.0 anymore.

New features of 5.4.1:

Enhanced usability for WebSMIT

Support for AIX 6.1 WPARs

NFS V4 Support (requires AIX 5.3 TL 7 or AIX 6.1)

New RPV Status monitor

Support for PPRC consisteny groups