No, sadly there will not be a next Harry Potter book.
There will not be another Harry Potter book.
All Harry Potter books are out. There won't be another book.
After Harry Potter and the Deathly Hallows there won't be another book or movie in the Harry Potter series.
There isn't one.
J.K Rowling has said she won't write another Harry Potter book.
There are no more books.
JK Rowling has decided to end The Series and she will write no more Harry Potter.
The next book? Harry Potter and the Deathly Hallows. And if you are interested, J.K. Rowling wrote another book: The Beedle and the Bard. Which is a book of short stories.
J.K. Rowling has stated several times that she is finished with Harry Potter and will not write another book.
There won't be anymore books.
After the seven, there won't be any more.