For users managing their game library via Atmosphere, Ryujinx, or Yuzu, a "base NSP" is useless without the corresponding "UPDATE NSP." The current gold standard for the Contra Anniversary Collection is Version 1.1.0 (sometimes listed as v65536 in hex editors).
Konami did not maintain a public live blog for these patches, but data miners and CFW testers have confirmed the following changes packed into the 250MB~ update file: Contra Anniversary Collection Switch NSP UPDATE
Konami usually excels here, and Contra is no exception. For users managing their game library via Atmosphere,