The Sun(an irreliable Bristish paper that isn't quite a tabloid) put those titles in the paper, and then practicaly the next day some other guys came out saying they were all wrong. Some people jumped the gun by copyrighting them, those are not the titles. Additionally Rowling has stated a number of times that the seventh book will be the final one in the HP universe. I personally would be tired of writing about the same thing for so long.
They say that the Sun tabloid edited the titles of the last two books:
"Harry Potter and the revolt of the half-blood" - 6th book
"Harry Potter and the research of the centaur" - 7th book