The fourth series of "Mahou Shoujo Lyrical Nanoha" was announced to start as a manga in Kadokawa's new magazine "Nyantype". The title is "Mahou Senki Lyrical Nanoha Force" and the first episode will be released on April 30th. Takamachi Nanoha is 25 years old in this series.

Key illustration of Nanoha Force

Original Story: Tsuzuki Masaki ("Lyrical Nanoha" Series)
Art: Higa Yukari

Source: Announcement of Nyantype

Edited on Mar 10th===================
Another manga series of Nanoha will start in Monthly Comp Ace May Issue. The title is "Mahou Shoujo Lyrical Nanoha ViVid" and the first episode will be released on May 26th. The story takes place four yeas after "Mahou Shoujo Lyrical Nanoha StrikerS".

Key illustration of Nanoha ViVid

Original Story: Tsuzuki Masaki
Art: Fujima Takuya ("Negima!? Neo")

Source: Fujima Takuya's blog