diff --git a/lib/extension/homeassistant.ts b/lib/extension/homeassistant.ts
index 290f547e..d63a8d82 100644
--- a/lib/extension/homeassistant.ts
+++ b/lib/extension/homeassistant.ts
@@ -1462,7 +1462,9 @@ export default class HomeAssistant extends Extension {
         }
 
         if (entity.isDevice() && entity.definition?.ota && message.hasOwnProperty('update')) {
-            message['update']['installed_version'] = entity.zh.softwareBuildID || 'unknown';
+            message['update']['installed_version'] = entity.zh.softwareBuildID ?
+                // Prepend with v: https://github.com/Koenkk/zigbee2mqtt/pull/15369
+                `v${entity.zh.softwareBuildID}` : 'unknown';
         }
     }
 
diff --git a/test/frontend.test.js b/test/frontend.test.js
index df088867..4eec04d7 100644
--- a/test/frontend.test.js
+++ b/test/frontend.test.js
@@ -197,7 +197,7 @@ describe('Frontend', () => {
         expect(MQTT.publish).toHaveBeenCalledTimes(1);
         expect(MQTT.publish).toHaveBeenCalledWith(
             'zigbee2mqtt/bulb_color',
-             stringify({state: 'ON', power_on_behavior:null, linkquality: null, update_available: null, update: {state: null, installed_version: "unknown"}}),
+             stringify({state: 'ON', power_on_behavior:null, linkquality: null, update_available: null, update: {state: null, installed_version: "v20.9"}}),
             { retain: false, qos: 0 },
             expect.any(Function)
         );
@@ -208,7 +208,7 @@ describe('Frontend', () => {
 
         // Received message on socket
         expect(mockWSClient.implementation.send).toHaveBeenCalledTimes(1);
-        expect(mockWSClient.implementation.send).toHaveBeenCalledWith(stringify({topic: 'bulb_color', payload: {state: 'ON', power_on_behavior:null, linkquality: null, update_available: null, update: {state: null, installed_version: "unknown"}}}));
+        expect(mockWSClient.implementation.send).toHaveBeenCalledWith(stringify({topic: 'bulb_color', payload: {state: 'ON', power_on_behavior:null, linkquality: null, update_available: null, update: {state: null, installed_version: "v20.9"}}}));
 
         // Shouldnt set when not ready
         mockWSClient.implementation.send.mockClear();
diff --git a/test/homeassistant.test.js b/test/homeassistant.test.js
index 5c3c7566..bea4fa49 100644
--- a/test/homeassistant.test.js
+++ b/test/homeassistant.test.js
@@ -956,7 +956,7 @@ describe('HomeAssistant extension', () => {
         expect(MQTT.publish).toHaveBeenCalledTimes(1);
         expect(MQTT.publish).toHaveBeenCalledWith(
             'zigbee2mqtt/bulb_color',
-            stringify({"color":{"hue": 0, "saturation": 100, "h": 0, "s": 100}, "color_mode": "hs", "linkquality": null, "state": null, "update_available": null, "power_on_behavior":null, "update": {"state": null, "installed_version": "unknown"}}),
+            stringify({"color":{"hue": 0, "saturation": 100, "h": 0, "s": 100}, "color_mode": "hs", "linkquality": null, "state": null, "update_available": null, "power_on_behavior":null, "update": {"state": null, "installed_version": "v20.9"}}),
             { retain: false, qos: 0 },
             expect.any(Function),
         );
@@ -972,7 +972,7 @@ describe('HomeAssistant extension', () => {
         expect(MQTT.publish).toHaveBeenCalledTimes(1);
         expect(MQTT.publish).toHaveBeenCalledWith(
             'zigbee2mqtt/bulb_color',
-            stringify({"color": {"x": 0.4576,"y": 0.41}, "color_mode": "xy", "linkquality": null,"state": null, "update_available": null, "power_on_behavior":null, "update": {"state": null, "installed_version": "unknown"}}),
+            stringify({"color": {"x": 0.4576,"y": 0.41}, "color_mode": "xy", "linkquality": null,"state": null, "update_available": null, "power_on_behavior":null, "update": {"state": null, "installed_version": "v20.9"}}),
             { retain: false, qos: 0 },
             expect.any(Function),
         );
@@ -988,7 +988,7 @@ describe('HomeAssistant extension', () => {
         expect(MQTT.publish).toHaveBeenCalledTimes(1);
         expect(MQTT.publish).toHaveBeenCalledWith(
             'zigbee2mqtt/bulb_color',
-            stringify({"linkquality": null,"state": "ON", "update_available": null, "power_on_behavior": null, "update": {"state": null, "installed_version": "unknown"}}),
+            stringify({"linkquality": null,"state": "ON", "update_available": null, "power_on_behavior": null, "update": {"state": null, "installed_version": "v20.9"}}),
             { retain: false, qos: 0 },
             expect.any(Function),
         );
diff --git a/test/stub/zigbeeHerdsman.js b/test/stub/zigbeeHerdsman.js
index a2e5c919..5a2a07f5 100644
--- a/test/stub/zigbeeHerdsman.js
+++ b/test/stub/zigbeeHerdsman.js
@@ -130,7 +130,7 @@ class Device {
 
 const returnDevices = [];
 
-const bulb_color = new Device('Router', '0x000b57fffec6a5b3', 40399, 4107, [new Endpoint(1, [0,3,4,5,6,8,768,2821,4096], [5,25,32,4096], '0x000b57fffec6a5b3', [], {lightingColorCtrl: {colorCapabilities: 254}})], true, "Mains (single phase)", "LLC020");
+const bulb_color = new Device('Router', '0x000b57fffec6a5b3', 40399, 4107, [new Endpoint(1, [0,3,4,5,6,8,768,2821,4096], [5,25,32,4096], '0x000b57fffec6a5b3', [], {lightingColorCtrl: {colorCapabilities: 254}})], true, "Mains (single phase)", "LLC020", false, undefined, null, '20.9');
 const bulb_color_2 = new Device('Router', '0x000b57fffec6a5b4', 401292, 4107, [new Endpoint(1, [0,3,4,5,6,8,768,2821,4096], [5,25,32,4096], '0x000b57fffec6a5b4', [], {lightingColorCtrl: {colorCapabilities: 254}}, [], null, null, {'scenes': {'1_0': {name: 'Chill scene', state: {state: 'ON'}}, '4_9': {state: {state: 'OFF'}}}})], true, "Mains (single phase)", "LLC020", false, 'Philips', '2019.09', '5.127.1.26581');
 const bulb_2 =  new Device('Router', '0x000b57fffec6a5b7', 40369, 4476, [new Endpoint(1, [0,3,4,5,6,8,768,2821,4096], [5,25,32,4096], '0x000b57fffec6a5b7', [], {lightingColorCtrl: {colorCapabilities: 17}})], true, "Mains (single phase)", "TRADFRI bulb E27 WS opal 980lm");
 const TS0601_thermostat =  new Device('EndDevice', '0x0017882104a44559', 6544,4151, [new Endpoint(1, [], [], '0x0017882104a44559')], true, "Mains (single phase)", 'kud7u2l');