According to Akitashoten, the voice cast of OVA "Aki-Sora
" was changed. The reason for the change was not announced. The OVA is about incest taboo between a brother and a sister and will be released on December 18th.
New cast (previously announced cast)
Aki: Kawaragi Shiho
Sora: Kinoshita Sayaka
Nami: Ueda Kana
Kana: Okajima Tae