The official website reads:
Dark Souls II: Scholar of the First Sin will be launching in the Americas on April 7, 2015 on Xbox 360, Xbox One, PS3, PS4, and PC/Steam.
Scholar of the First Sin will include the three previously released DLC packs – Crown of the Sunken King, Crown of the Old Iron King, and Crown of the ivory King – along with additional features.
All versions of the game will include the following features (Existing Dark Souls II owners will receive a patch to implement these elements):
Additional NPCs added for an enhanced story experience.
Parameter adjustments for improved game balance.
Augmented item descriptions.
Improved online matchmaking functionality.
Xbox One, PS4, and DirectX 11 versions of the game will include the following features (in addition to those listed above):
Additional upgrades to graphics, sound, performance.
Increase in maximum online players in single session.