In the post yesterday on the inscription found at Kalefeld that mentions LEGIIII, I wrote that the legion, Legio IIII Flavia Felix was attested in the region thanks to an inscription: CIL XIII 6104/ILS2310. I couldn't lay my hands on it then. For those interested, here it is:
d. m. Aur. Vitali | mil. leg. IIII Fl, | stip. VII, vlxit | ann. XXV, agens | expeditione | Germaniae, Fl|avius Proc|lus mil. leg. s. s.,| secundus he|res contuber|nali bene mere[nti] f. c.
Also another piece on the discovery at NDR.de.