A new opening will debut for the anime on April 5th, performed by the EXILE Tribe band.
Credit for finding this goes to sandman and ANN.
It seems the next opening song is called "Head Knock Days".
This year's 18th issue of Shueisha's Weekly Shonen Jump magazine is announcing on Monday that the all-male group Generations from EXILE Tribe will perform the new opening theme song for the One Piece television anime. The song "Hard Knock Days" will begin playing in the anime on April 5. Generations from EXILE Tribe is a seven-member unit that formed in 2011 under the Exile spinoff umbrella unit EXILE Tribe. They already performed the theme songs for the Japanese live-action Sugarless series and the Japanese release of the American live-action series Arrow, among other projects.