Weekly Famitsu announces in their July 7th issue no. 1751 will have a column on the 20 year history of .hack as well as the "20th anniversary event". Not much is known about this event yet, but you can check the announcement on Kadokawa.
Weekly Famitsu July 7, 2022 Issue No.1751 will hit store shelves on Thursday June 23, 2022 and is available for preorder on Amazon Japan at ¥580 plus shipping. International shipping is available.