If you have a modded Switch running Custom Firmware, the process to install an update or DLC is as follows:
This white paper examines the technical architecture of Splatoon 3’s post-launch update cycle, focusing on the delivery mechanism via NSP (Nintendo Submission Package) formats and the integration of the "Side Order" DLC (part of the Expansion Pass). As of April 2026, Splatoon 3 has completed its two-year content roadmap, including 10 major catalog updates (versions 1.1.0 through 9.0.0) and the final DLC wave. This document details file structure, delta patching efficiency, and forensic indicators for update integrity.
As of this paper’s publication: