Three new episodes of "Azumanga Daioh
" will be published in the new magazine Monthly Shounen Sunday. The first episode will be out on May 12th.
Revised editions of Azumanga Daioh will be published from June 11th to celebrate its 10th anniversary. The original four volumes will be re-edited into three volumes and each volume has a new 16-page episode. These new episodes will also be published in Monthly Shounen Sunday for the promotion.
Source: Yotsuba Studio Official Website