Michele, 

currently I do PH release updates in several Y2K projects (yes, starting
from
version 4.0 !) and I have compiled (for my own sake) a list of differences 
between the releases to watch out for,

If you are interested, I`ll send some more details; but on your relevant
question:

1. You should do some scanning for new reserved words (see manual)

2. Watch the occurrence of procedure FIND with ... FOR ... construct.

3. Dangerous: (QDESIGN) FILE ... OCCURS WITH ... RESET AT STARTUP
   (QDESIGN only issues a warning, not an error - and changes the function
!)

While you are at it - lookout for redefined keys (specially in KSAM files),
that are
used in a SILENT ... LOOKUP NOTON ... construct. The lookup noton may not
work in every case and lead to duplicates. This bug has occurred with
release
7 and to my knowledge never been documented or resolved.

Good luck
Elisabeth