The Shop Tsutaya page for Jigoku Shoujo's omnibus volume titled Kachou Fuuketsu lists that the series will get a new anime season. It is slated for Summer 2017.
Jigoku Shoujo is an original anime produced by Studio Deen. Three seasons were broadcast in Fall 2005, Fall 2006, and Fall 2008. A manga version was serialized irregularly by Miyuki Eto in Nakayoshi between 2005 and 2008 with nine compiled volumes. The manga received two sequels; the first, titled Shin Jigoku Shoujo, was serialized from 2008 to 2009 with three compiled volumes, and the second, titled Jigoku Shoujo R, was serialized from 2009 to 2013 with eleven compiled volumes.
Update March 3
The official website and Twitter have been opened and announced that the title for the new TV anime will be Jigoku Shoujo: Yoi no Togi. The series is scheduled to air on MBS, Tokyo MX, Gunma TV, Tochigi TV, and BS 11. It will consist of six new episodes and six selective old episodes. While cast and most of staff members will reprise their roles, Takahiro Omori, who directed first two seasons, will return to direct instead of Hiroshi Watanabe, who directed third season. A teaser PV and a key visual have also been revealed.
Note: The video is region-locked; click here for an alternative link.