Yes, there was a change:
http://www.sfml-dev.org/documentation/2.0/classsf_1_1Texture.php#ae9a4274e7b95ebf7244d09c7445833b0
DotNet has something similar now because there was release of 2.0 recently.
There's a static method that takes null or texture:
public static void Bind(Texture texture)
{
sfTexture_bind(texture != null ? texture.CPointer : IntPtr.Zero);
}