If you ever want to use Fall of the Rising Sun (FotRS), Trigger Maru Overhauled (TMO), Real Fleet Boat (RFB), or Operation Monsun, you must have v1.5. Modern mods are coded exclusively for the 1.5 executable. Trying to install them on v1.4 will result in a CTD (Crash to Desktop).
Officially titled the "U-Boat Missions Add-On Patch," version 1.5 was the final official update released by Ubisoft. It served a dual purpose:
"The patch says 'Silent Hunter 4 not found'." Silent Hunter 4 1.5 Patch Download
"The game crashes when I start the U-Boat campaign."
"The water is purple/black."
Installing the 1.5 patch requires precision. Do not rush.
Prerequisites:
The Process: