Bandai Namco Entertainment Europe previously announced the release date of Dark Souls: Remastered for all platforms to be on 25th of May, 2018. The release date for the Nintendo Switch version has now been pushed back to this summer. Additionally, Solaire of Astora amiibo has also been postponed to the same timeframe. The Nintendo Switch version of Dark Souls: Remastered allows players to play it anytime and anywhere.
Dark Souls: Remastered will still be available on 25th of May, 2018 for the PlayStation 4, Xbox One, and PC.
Source: Bandai Namco press email