Then I would not use "only."
I think it probably won't be released until next year.
If you must: I think it will only be released next year.
By putting it next to "next year" (in the future) it sounds as though you are restricting its release to next year, and and next year only.
(As Philip said in the past, it emphasizes how recently it happened: It was released only last year, and already it's obsolete.)