“Do I think they have the capacity to make a hydrogen bomb? I think that’s virtually impossible,” said Daniel Pinkston, an expert on North Korea’s nuclear weapons who is currently at Babes-Bolyai University in Romania.
…South Korean intelligence specialists also were skeptical and dismissed Kim’s words as rhetoric. “We don’t have any information that North Korea has developed an H-bomb,” Yonhap News Agency quoted an unidentified intelligence official as saying. “We do not believe that North Korea, which has not succeeded in miniaturizing nuclear bombs, has the technology to produce an H-bomb.”
That is from The Washington Post, December 10, 2015. It remains to be seen, of course, whether the test actually was a hydrogen bomb.