Direct proof of use
Oryx documents the 85 mm D-44 divisional gun in the Yemeni Army's pre-war equipment inventory and states that its Yemen list was intended to clarify what military equipment was available to Yemeni parties on the battlefield after the Houthi takeover and the start of the civil-war period.
That evidence supports the D-44 as legacy Yemeni battlefield materiel in the 2014 Yemen Civil War. It does not, by itself, identify a particular wartime operator, battery, location, or dated firing incident.
Sources: Handbook Of Pre-War Yemeni Fighting Vehicles
Timeline
A CSIS military-balance study from the early 1990s listed Yemen as having 100 D-44 85 mm weapons among a mixed and largely obsolete towed-artillery inventory.
In September 2015, Oryx listed the 85 mm D-44 divisional gun among equipment in Yemeni Army service before the 2014-2015 Houthi takeover and framed the list as battlefield-availability context for Yemeni parties.
Sources: CSIS Yemen and Red Sea Military Balance, Handbook Of Pre-War Yemeni Fighting Vehicles
Narrative
The D-44 was a Soviet 85 mm field and antitank gun that remained in post-Cold War inventories long after newer artillery and antitank systems replaced it in front-line Soviet service. The U.S. Army describes the D-44 as a split-trail gun derived from the T-34-85's 85 mm gun family and capable of firing high-explosive, incendiary, and armor-piercing ammunition.
Yemen's D-44 context is therefore best treated as legacy towed artillery rather than a documented modern transfer. CSIS described Yemen's towed-artillery holdings as a mixed inventory from 85 mm to 155 mm, and Oryx later placed the D-44 in the pre-war Yemeni Army equipment pool available to battlefield parties. The public record used here supports possession and conflict-period availability, not confirmed side-specific employment.
Sources: RIA Self-Guided Tour: M1945 (D44) 85MM Antitank Gun, CSIS Yemen and Red Sea Military Balance, Handbook Of Pre-War Yemeni Fighting Vehicles