diff --git a/public/locales/de-DE/translation.json b/public/locales/de-DE/translation.json
index 5f7d6a9..5423267 100644
--- a/public/locales/de-DE/translation.json
+++ b/public/locales/de-DE/translation.json
@@ -405,6 +405,7 @@
     "deployment-id": "Deployment-ID",
     "decision-requirements-id": "Entscheidungsanforderungs-Definitions-ID",
     "history-ttl": "Verlaufs-Aufbewahrungsdauer",
+    "history-ttl-updated": "Verlaufs-Aufbewahrungsdauer aktualisiert.",
     "sort": {
       "name": "Name",
       "key": "Schlüssel",
diff --git a/public/locales/en-US/translation.json b/public/locales/en-US/translation.json
index ac20fbe..8dc1bea 100644
--- a/public/locales/en-US/translation.json
+++ b/public/locales/en-US/translation.json
@@ -405,6 +405,7 @@
     "deployment-id": "Deployment ID",
     "decision-requirements-id": "Decision Requirements Definition ID",
     "history-ttl": "History Time To Live",
+    "history-ttl-updated": "History time to live updated.",
     "sort": {
       "name": "Name",
       "key": "Key",
diff --git a/public/locales/es-ES/translation.json b/public/locales/es-ES/translation.json
index 121792c..2faed2a 100644
--- a/public/locales/es-ES/translation.json
+++ b/public/locales/es-ES/translation.json
@@ -372,6 +372,7 @@
     "deployment-id": "ID de despliegue",
     "decision-requirements-id": "ID de definición de requisitos de decisión",
     "history-ttl": "Tiempo de vida del historial",
+    "history-ttl-updated": "Tiempo de vida del historial actualizado.",
     "sort": {
       "name": "Nombre",
       "key": "Clave",
diff --git a/public/locales/fr-FR/translation.json b/public/locales/fr-FR/translation.json
index 43e715f..3218868 100644
--- a/public/locales/fr-FR/translation.json
+++ b/public/locales/fr-FR/translation.json
@@ -372,6 +372,7 @@
     "deployment-id": "ID de déploiement",
     "decision-requirements-id": "ID de définition des exigences de décision",
     "history-ttl": "Durée de conservation de l'historique",
+    "history-ttl-updated": "Durée de conservation de l'historique mise à jour.",
     "sort": {
       "name": "Nom",
       "key": "Clé",
diff --git a/public/locales/nl-NL/translation.json b/public/locales/nl-NL/translation.json
index a27f3a1..2813b96 100644
--- a/public/locales/nl-NL/translation.json
+++ b/public/locales/nl-NL/translation.json
@@ -372,6 +372,7 @@
     "deployment-id": "Deployment-ID",
     "decision-requirements-id": "Beslissingsvereisten-definitie-ID",
     "history-ttl": "Bewaartermijn geschiedenis",
+    "history-ttl-updated": "Bewaartermijn geschiedenis bijgewerkt.",
     "sort": {
       "name": "Naam",
       "key": "Sleutel",
diff --git a/src/api/resources/decision.js b/src/api/resources/decision.js
index a2c3857..17d9a0d 100644
--- a/src/api/resources/decision.js
+++ b/src/api/resources/decision.js
@@ -1,4 +1,4 @@
-import { GET, GET_TEXT } from '../helper.jsx'
+import { GET, PUT } from '../helper.jsx'
 
 
 const get_decision_definition = (state, id) =>
@@ -13,11 +13,20 @@ const get_decision_definitions = (state, params = {}) => {
 const get_dmn_xml = (state, id) =>
   GET(`/decision-definition/${id}/xml`, state, state.api.decision.dmn)
 
+const update_history_ttl = (state, id, historyTimeToLive) =>
+  PUT(
+    `/decision-definition/${id}/history-time-to-live`,
+    { historyTimeToLive },
+    state,
+    state.api.decision.update_history_ttl,
+  )
+
 
 const decision = {
   get_decision_definition,
   get_decision_definitions,
   get_dmn_xml,
+  update_history_ttl,
 }
 
 export default decision
diff --git a/src/api/resources/decision.test.js b/src/api/resources/decision.test.js
index 2a7a0e7..e2b996c 100644
--- a/src/api/resources/decision.test.js
+++ b/src/api/resources/decision.test.js
@@ -3,9 +3,10 @@ import { describe, it, vi, beforeEach } from "vitest";
 vi.mock("../helper.jsx", () => ({
   GET: vi.fn(),
   GET_TEXT: vi.fn(),
+  PUT: vi.fn(),
 }));
 
-import { GET } from "../helper.jsx";
+import { GET, PUT } from "../helper.jsx";
 import { create_mock_state, expect_api_call } from "../../test/helpers.js";
 import decision from "./decision.js";
 
@@ -41,4 +42,14 @@ describe("api/resources/decision", () => {
       signal: state.api.decision.dmn,
     });
   });
+
+  it("update_history_ttl() PUTs the history time to live", () => {
+    decision.update_history_ttl(state, "dec-1", 30);
+    expect_api_call(PUT, {
+      url: "/decision-definition/dec-1/history-time-to-live",
+      body: { historyTimeToLive: 30 },
+      state,
+      signal: state.api.decision.update_history_ttl,
+    });
+  });
 });
diff --git a/src/pages/Decisions.jsx b/src/pages/Decisions.jsx
index 9a73c30..d79a05d 100644
--- a/src/pages/Decisions.jsx
+++ b/src/pages/Decisions.jsx
@@ -1,4 +1,5 @@
 import { useContext, useEffect } from 'preact/hooks'
+import { useSignal, useSignalEffect } from '@preact/signals'
 import { useTranslation } from 'react-i18next'
 import { AppState } from '../state.js'
 import { useLocation, useRoute } from 'preact-iso'
@@ -170,9 +171,24 @@ const DecisionsList = () => {
 
 const DecisionDetails = () => {
   const state = useContext(AppState),
-    { api: { decision: { definition, dmn } } } = state,
-    { params: { decision_id } } = useRoute(),
-    [t] = useTranslation()
+    { api: { decision: { definition, dmn, update_history_ttl } } } = state,
+    [t] = useTranslation(),
+    history_ttl = useSignal('')
+
+  useSignalEffect(() => {
+    history_ttl.value = definition.value?.data?.historyTimeToLive ?? ''
+  })
+
+  const submit_history_ttl = async (e, id) => {
+    e.preventDefault()
+    const raw = history_ttl.peek()
+    await engine_rest.decision.update_history_ttl(
+      state,
+      id,
+      raw === '' ? null : Number(raw),
+    )
+    void engine_rest.decision.get_decision_definition(state, id)
+  }
 
   return <div id="decision-details">
     <RequestState
@@ -182,7 +198,6 @@ const DecisionDetails = () => {
         const {
           id, key, name, version, versionTag, tenantId, deploymentId,
           decisionRequirementsDefinitionId, historyTimeToLive,
-          resource
         } = definition.value.data
 
         return <div>
@@ -207,6 +222,17 @@ const DecisionDetails = () => {
             <dt>{t("decisions.history-ttl")}</dt>
             <dd>{historyTimeToLive}</dd>
           </dl>
+          <RequestState
+            signal={update_history_ttl}
+            on_nothing={() => <></>}
+            on_success={() => <p class="success">{t("decisions.history-ttl-updated")}</p>} />
+          <form class="history-ttl-form" onSubmit={(e) => submit_history_ttl(e, id)}>
+            <label for="decision-history-ttl">{t("decisions.history-ttl")}</label>
+            <input id="decision-history-ttl" name="historyTimeToLive" type="number" min="0" step="1"
+                   value={history_ttl.value}
+                   onInput={(e) => (history_ttl.value = e.currentTarget.value)} />
+            <button type="submit">{t("common.save")}</button>
+          </form>
         </div>
       }} />
 
diff --git a/src/pages/Decisions.test.jsx b/src/pages/Decisions.test.jsx
index 9ac0a45..8306ff3 100644
--- a/src/pages/Decisions.test.jsx
+++ b/src/pages/Decisions.test.jsx
@@ -1,6 +1,6 @@
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 import { h } from "preact";
-import { render, cleanup } from "@testing-library/preact";
+import { render, cleanup, fireEvent } from "@testing-library/preact";
 
 // Spy all engine_rest API functions but keep RequestState/RESPONSE_STATE real.
 vi.mock("../api/engine_rest.jsx", async (importOriginal) => {
@@ -79,4 +79,52 @@ describe("DecisionsPage", () => {
     const { getByTestId } = renderPage(state);
     expect(getByTestId("dmn-viewer").textContent).toBe("<dmn>xml</dmn>");
   });
+
+  it("updates the decision definition history time to live", async () => {
+    mockParams = { decision_id: "d1" };
+    signal_response(state.api.decision.definition, {
+      id: "d1",
+      key: "risk",
+      name: "Risk",
+      version: 1,
+      historyTimeToLive: 30,
+    });
+    const { container, getByLabelText } = renderPage(state);
+
+    fireEvent.input(getByLabelText("decisions.history-ttl"), {
+      target: { value: "45" },
+    });
+    fireEvent.submit(container.querySelector("form.history-ttl-form"));
+    await Promise.resolve();
+
+    expect(engine_rest.decision.update_history_ttl).toHaveBeenCalled();
+    const call = engine_rest.decision.update_history_ttl.mock.lastCall;
+    expect(call[0]).toBe(state);
+    expect(call[1]).toBe("d1");
+    expect(call[2]).toBe(45);
+  });
+
+  it("clears the decision definition history time to live with an empty value", async () => {
+    mockParams = { decision_id: "d1" };
+    signal_response(state.api.decision.definition, {
+      id: "d1",
+      key: "risk",
+      name: "Risk",
+      version: 1,
+      historyTimeToLive: 30,
+    });
+    const { container, getByLabelText } = renderPage(state);
+
+    fireEvent.input(getByLabelText("decisions.history-ttl"), {
+      target: { value: "" },
+    });
+    fireEvent.submit(container.querySelector("form.history-ttl-form"));
+    await Promise.resolve();
+
+    expect(engine_rest.decision.update_history_ttl).toHaveBeenCalled();
+    const call = engine_rest.decision.update_history_ttl.mock.lastCall;
+    expect(call[0]).toBe(state);
+    expect(call[1]).toBe("d1");
+    expect(call[2]).toBeNull();
+  });
 });
diff --git a/src/state.js b/src/state.js
index f63ad2e..f50c392 100644
--- a/src/state.js
+++ b/src/state.js
@@ -164,6 +164,7 @@ const createAppState = () => {
       definitions: signal(null),
       definition: signal(null),
       dmn: signal(null),
+      update_history_ttl: signal(null),
       saved_filters: signal(null),
     },
     history: {