Xbox One, PC and PlayStation 4 owners can still look forward to getting the game on May 25th, but Switch owners have to wait a few more months. No specific reason was given for the delay, but recent hands on impressions were favourable, so its likely something big.
Due to the nature of causality, we must announce that the Nintendo Switch version of #DarkSoulsRemastered will be pushed back to summer of 2018, and with it, the release of the Solaire of Astora amiibo.— Dark Souls (@DarkSoulsGame) April 17, 2018
PC/PS4/X1 versions will maintain their May 25th release date.
As an aside, the Solaire of Astora amiibo has also been delayed, it will still release the same day as the Switch version of the game, whenever that happens to be.