According to a joint announcement on their website the duo is no longer

“The reason is not due to artistic differences or lack of wanting to continue, nor any health issues as both Meg and Jack are feeling fine and in good health,” the statement reads. “It is for a myriad of reasons, but mostly to preserve what is beautiful and special about the band have it stay that way.”
White Stripes

“The White Stripes do not belong to Meg and Jack anymore. The White Stripes belong to you now and you can do with it whatever you want. The beauty of art and music is that it can last forever if people want it to. Thank you for sharing this experience. Your involvement will never be lost on any of us and we are truly grateful.”

Look for more and more of their side projects to appear. Pretty great way to end it if you ask me.