Since there is no official free patch from version 1.4 to 1.5, you can obtain it through the following methods:
If you are installing the game today, follow this specific order to ensure a smooth experience: Silent Hunter 4 1.5 Patch Download
American skippers aren't left out. The 1.5 patch introduces the (the ultimate US diesel boat) and properly refines the Balao-class with correct late-war radar and AA suites. Since there is no official free patch from version 1
"The patch says 'Silent Hunter 4 not found'." Just remember: download from The Internet Archive, apply
Whether you want to hunt convoys in a German U-boat off South Africa or command an American Gato-class through the Slot at Guadalcanal, the 1.5 patch is your ticket. Just remember: download from The Internet Archive, apply the 4GB patch, and install Fall of the Rising Sun . You will not need another game for the next 500 hours.
Silent Hunter 4: Wolves of the Pacific remains a titan of the submarine simulation genre, but its journey from launch to legendary status was paved by one critical update: the v1.5 patch. Released alongside the U-Boat Missions expansion, this patch is widely considered the "definitive" version of the game, transforming a bug-riddled release into a polished, high-fidelity naval masterpiece.