According to an email sent to customers, the reason was "a delay in the manufacturing process."
The Blu-ray will include nine art cards, each featuring an individual member of Aqours, and a landscape orientated poster. It will also feature promo videos and textless versions of the opening and closing sequences.
Anime Limited describes the series:
"In spite of their previous setbacks, the members of Aqours are working harder than ever to save Uranohoshi Girls' High School from being shut down as the second term begins.
"With another Love Live event already on the way, their ultimate goal of winning the contest and saving their school is in clear sight… but is there enough time to achieve their dreams before the clock runs down and the school is closed? With all manner of new hardships facing them, the Aqours girl's friendships and dedication will be tested to the limit while they endeavour to awaken the power of their collective talent, and hope to shine as they seek to cement their place in Love Live history."