Lots of folks still use P4 , even if they do have later versions.  Sometimes it's just faster and less taxing for some tasks.

There was a thread earlier this year (in here I believe) by someone else looking for the 4.03 upgrade, but it digressed into a misguided discussion of warez, and, IIRC, the originator never indicated that he'd found a current source for the update.

If I'm wrong, or if anyone does know where the update can still be legally obtained, please let us know here.