Hello James -
The upgrade document for 3.5.2 to 4.0.1 can be found on the Software download site:
https://software.arcsight.com > ESM > Builds > Previous_Builds > 4.0-SP1 > Documentation
The ArcSight Support team can test your 3.5 system to ensure the ugprade goes smoothly - just open a support incident and we can assist. This testing is free of charge and I highly recommend it.
Hope this helps!
I do not find the 3.5 to 4.0 documentation. Please open a support case. We must do an upgrade verification based on your system table dump (ArcSight Support does this internally). At the same time, you can clarify the upgrade process itself.
There are critical differences that come to play in your upgrade path i.e., schema is changed as well as the DB version. Your upgrade path is:3.5 to 4.0 SP1
4.0SP1 to 4.0SP3
4.0SP3 to 4.5SP1