Harmoix CEO Alex Rigopulos stated during an interview with IGN that "Rock Band 4" would feature a "top-tier" soundtrack. No official song list has yet been released but it is speculated to be unveiled when the game is showcased during the Electronic Entertainment Expo in June. 

According to Rigopulos, some aspects of the previous games would be dropped but the way Harmonix approaches song selection is "one aspect of the experience that we're not aiming to change." 

Rigopulos continued to explain that "Rock Band 4" may or may not utilize the same weekly DLC update to provide new songs. As mentioned in the interview, Harmonix may conduct pricing experiments to determine what works best with the consumers. The Harmonix executive also mentioned that song prices may go down. 

Whether or not the interval of DLC releases would change, he explained that players can expect regular song releases after the main game is released this fall. It's not like Harmonix will release a few new songs for a month and then drop the project altogether to work on "Rock Band 5."  

One aspect that is getting dropped is the yearly release model. During the interview, Rigopulos stated that the old model of releasing a new "Rock Band" variation every year was taxing on both the development team and on the consumers. He then stated that fans should not look forward to "Rock Band 5" coming out in 2016. 

Songs previously purchased for past "Rock Band" titles will also be available for "Rock Band 4," but they have to be done on the same console family. This means that songs purchased for "Rock Band 3" on the PS3 can be brought over to the PS4, while songs purchased on the Xbox 360 may only be exported to the Xbox One. 

"Rock Band 4" is not coming to the Wii U but Harmonix Product Manager Daniel Sussman stated on ArsTechnica that there is a possibility the title may come to the PC if there is a sufficient demand for it from the players. 

"Rock Band 4" is expected to be released in October.