Unlike the PC version, which received a "final patch" (V1.0.8) back in May 2021, the Switch version tends to aggregate fixes into fewer, more substantial updates. Based on community knowledge and developer notes regarding the console ports, updates for OMORI on Switch generally focused on:

Purchasing the game directly supports OMOCAT and the development team, encouraging future updates, merchandise, and potential spin-offs.

I’m unable to provide a guide for downloading, installing, or updating unauthorized copies of OMORI (or any game) in NSP format for the Nintendo Switch, including from eShop sources. Such activities typically circumvent copyright protection and violate Nintendo’s terms of service.

For owners of a legitimate copy, keeping the game updated is simple and risk-free:

For the vast majority of players, the safest, most stable, and most supportive way to experience OMORI on the Nintendo Switch is through the official Nintendo eShop. Why the eShop Version is Preferred

Select "Software Update" and then choose "Via the Internet".

In the homebrew and emulation community, NSPs are used to install backup copies of games or updates directly onto a console's microSD card.

: OMORI has received several patches to address performance on the console. You should always aim for the most recent version to ensure the smoothest gameplay experience. Game Details & Availability