*  See all OS maintenance levels the machine is aware of:
        # instfix -i | grep AIX_ML
   * See all packages which are downlevel for a certain maintenance level:
     At least the machine has to be aware of the maintenance level in question. List all the maintenance levels the machine is aware of (see there). Use the displayed keyword as argument for instfix and grep for ":-:' to get all packages downlevel for this ML.

     # instfix -i | grep AIX_ML
     # instfix -ick <ML_Keyword> | grep ':-:'

     Example: Find all filesets downlevel relative to ML03
     # instfix -i | grep AIX_ML
     All filesets for 5.1.0.0_AIX_ML were found.
     All filesets for 5100-01_AIX_ML were found.
     All filesets for 5100-02_AIX_ML were found.
     Not all filesets for 5100-03_AIX_ML were found.
     Not all filesets for 5100-04_AIX_ML were found.
     Not all filesets for 5100-05_AIX_ML were found.
     Not all filesets for 5100-06_AIX_ML were found.

     # instfix -ick 5100-03_AIX_ML | grep ':-:'
     5100-03_AIX_ML:IMNSearch.rte.httpdlite:2.0.0.15:2.0.0.15:-:AIX 5100-03 Update
     5100-03_AIX_ML:X11.adt.imake:5.1.0.15:5.1.0.15:-:AIX 5100-03 Update
     5100-03_AIX_ML:X11.apps.xdm:5.1.0.25:5.1.0.25:-:AIX 5100-03 Update

     Update IMNSearch.rte.httpdlite, X11.adt.imake and X11.apps.xdm to get to ML03.
      
   * is apar .......... installed on the system 

     # instfix -iak IZ31313