: If you already own the base game (v1.0 to v1.4), you can purchase the U-Boat Missions Add-On separately on platforms like Steam .
If you need help or fixing resolution issues on Windows 11: Subsim community compatibility fixes Step-by-step JSGME mod manager guide Comparison of American vs. German campaign mechanics
: This is the final free official patch. It can be downloaded from community sites like the SUBSIM Radio Room .