Direct proof of use
The D-20's documented Yemen-war connection comes from legacy Yemeni Army artillery stocks rather than a later foreign transfer record. Oryx listed the 152 mm D-20 gun-howitzer under Yemeni Army towed artillery in a September 2015 inventory that covered equipment in service before the 2014-2015 Houthi takeover and described that inventory as materiel available to Yemeni parties on the battlefield.
That source supports the D-20 as a fielded legacy artillery system in the 2014 Yemen Civil War. It does not by itself identify a specific D-20 battery, firing unit, target, or dated fire mission.
Sources: Handbook Of Pre-War Yemeni Fighting Vehicles
Timeline
Yemen's 2014-2015 political and military collapse split former state stocks across rival forces. Oryx's September 2015 inventory placed the D-20 in the pre-war Yemeni Army artillery park after the Houthi takeover had already turned those stocks into contested battlefield materiel.
The D-20 should therefore be treated as a conflict-use entry for inherited Yemeni artillery stocks, not as evidence of a separately documented wartime acquisition.
Sources: CFR Yemen and Red Sea Tracker, Handbook Of Pre-War Yemeni Fighting Vehicles
Role in the conflict
As a 152 mm towed gun-howitzer, the D-20 fits the conflict's conventional fire-support layer: heavy indirect fire from legacy army depots and front-line artillery positions. U.S. Army ODIN identifies the D-20 as a Russian/Soviet 152 mm towed gun-howitzer, while WeaponSystems.net describes its split-trail carriage, 34-caliber ordnance, and 17.4 km standard maximum range.
For the Yemen record, the supported claim is narrower than many generic artillery reports from the war. The available source-backed entry is that D-20s were part of the pre-war Yemeni Army inventory and were available to battlefield parties after the Houthi takeover; individual shelling incidents should not be attributed to the D-20 without separate weapon-specific evidence.
Sources: D-20 (M1955) Russian 152mm Towed Gun-Howitzer, 152mm D-20, Handbook Of Pre-War Yemeni Fighting Vehicles