diff --git a/frontend/src/components/immersive-editor/DrawerTrigger.vue b/frontend/src/components/immersive-editor/DrawerTrigger.vue
index dc2845e294..217847c8d4 100644
--- a/frontend/src/components/immersive-editor/DrawerTrigger.vue
+++ b/frontend/src/components/immersive-editor/DrawerTrigger.vue
@@ -2,7 +2,7 @@
     <button
         title="Toggle drawer"
         class="drawer-trigger"
-        :class="{ 'hidden': isHidden }"
+        :class="{ 'hidden': isHidden, 'nr5-plus': isNr5Plus }"
         :aria-label="isHidden ? 'Open drawer' : 'Close drawer'"
         :aria-expanded="!isHidden"
         type="button"
@@ -25,6 +25,10 @@ export default {
         isHidden: {
             type: Boolean,
             default: false
+        },
+        isNr5Plus: {
+            type: Boolean,
+            default: false
         }
     },
     emits: ['toggle']
@@ -42,6 +46,20 @@ export default {
     .ff-layout--immersive--fullscreen & {
         top: 10px;
     }
+
+    &.nr5-plus {
+        top: 63px;
+        padding: 8px;
+
+        .ff-btn--icon {
+            display: none;
+        }
+
+        .ff-layout--immersive--fullscreen & {
+            top: 4px;
+        }
+    }
+
     left: 0;
     z-index: 100;
     padding: 8px 2px 8px 8px;
diff --git a/frontend/src/pages/admin/Template/sections/Editor.vue b/frontend/src/pages/admin/Template/sections/Editor.vue
index f304189d9c..a024cd318c 100644
--- a/frontend/src/pages/admin/Template/sections/Editor.vue
+++ b/frontend/src/pages/admin/Template/sections/Editor.vue
@@ -206,6 +206,7 @@ import FormHeading from '../../../../components/FormHeading.vue'
 import FormRow from '../../../../components/FormRow.vue'
 import FeatureUnavailableToTeam from '../../../../components/banners/FeatureUnavailableToTeam.vue'
 import timezonesData from '../../../../data/timezones.json'
+import { isInstanceOnNR5Plus } from '../../../../utils/instanceVersion'
 import ChangeIndicator from '../components/ChangeIndicator.vue'
 import LockSetting from '../components/LockSetting.vue'
 
@@ -242,11 +243,7 @@ export default {
     emits: ['update:modelValue'],
     data () {
         return {
-            timezones: timezonesData.timezones,
-            defaultThemes: [
-                { label: 'FlowFuse Light', value: 'forge-light' },
-                { label: 'FlowFuse Dark', value: 'forge-dark' }
-            ] // FUTURE: Get from theme plugins
+            timezones: timezonesData.timezones
         }
     },
     computed: {
@@ -291,6 +288,20 @@ export default {
             }
             return SemVer.satisfies(SemVer.coerce(launcherVersion), '>=2.12.0')
         },
+        instanceOnNR5Plus () {
+            return isInstanceOnNR5Plus(this.instance)
+        },
+        defaultThemes () {
+            // NR5+ runtime gate collapses Light/Dark to `forge`; show one option.
+            // Admin Template stays version-agnostic since it targets any NR version.
+            if (!this.editTemplate && this.instanceOnNR5Plus) {
+                return [{ label: 'FlowFuse', value: 'forge' }]
+            }
+            return [
+                { label: 'FlowFuse Light', value: 'forge-light' },
+                { label: 'FlowFuse Dark', value: 'forge-dark' }
+            ]
+        },
         themeOptions () {
             if (this.modelValue?.settings?.theme && !this.defaultThemes.map(th => th.value).includes(this.modelValue.settings.theme)) {
                 // set the custom theme as one of the available options
diff --git a/frontend/src/pages/device/Editor/index.vue b/frontend/src/pages/device/Editor/index.vue
index 7633b449cb..42f4711f92 100644
--- a/frontend/src/pages/device/Editor/index.vue
+++ b/frontend/src/pages/device/Editor/index.vue
@@ -34,6 +34,7 @@
 
             <DrawerTrigger
                 :is-hidden="editorImmersiveDrawer.state"
+                :is-nr5-plus="isDeviceOnNR5Plus"
                 @toggle="toggleEditorImmersiveDrawer"
             />
         </div>
@@ -72,6 +73,7 @@ import EditorWrapper from '../../../components/immersive-editor/RemoteInstanceEd
 import { useDeviceHelper } from '../../../composables/DeviceHelper.js'
 import usePermissions from '../../../composables/Permissions.js'
 import Alerts from '../../../services/alerts.js'
+import { isInstanceOnNR5Plus } from '../../../utils/instanceVersion'
 
 import DeviceAssignApplicationDialog from '../../team/Devices/dialogs/DeviceAssignApplicationDialog.vue'
 import DeviceAssignInstanceDialog from '../../team/Devices/dialogs/DeviceAssignInstanceDialog.vue'
@@ -140,6 +142,9 @@ export default {
         isExpertRoute () {
             return this.$route.name === 'device-editor-expert'
         },
+        isDeviceOnNR5Plus () {
+            return isInstanceOnNR5Plus(this.device)
+        },
         isDevModeAvailable: function () {
             return !!this.features.deviceEditor
         },
diff --git a/frontend/src/pages/instance/Editor/index.vue b/frontend/src/pages/instance/Editor/index.vue
index 4dc3796089..f8f25607a3 100644
--- a/frontend/src/pages/instance/Editor/index.vue
+++ b/frontend/src/pages/instance/Editor/index.vue
@@ -35,6 +35,7 @@
 
             <DrawerTrigger
                 :is-hidden="editorImmersiveDrawer.state"
+                :is-nr5-plus="isInstanceOnNR5Plus"
                 @toggle="toggleEditorImmersiveDrawer"
             />
         </div>
@@ -60,6 +61,7 @@ import InstanceActionsButton from '../../../components/instance/ActionButton.vue
 import usePermissions from '../../../composables/Permissions.js'
 import instanceMixin from '../../../mixins/Instance.js'
 
+import { isInstanceOnNR5Plus } from '../../../utils/instanceVersion'
 import { Roles } from '../../../utils/roles.js'
 import ConfirmInstanceDeleteDialog from '../Settings/dialogs/ConfirmInstanceDeleteDialog.vue'
 import DashboardLink from '../components/DashboardLink.vue'
@@ -166,6 +168,9 @@ export default {
         },
         isExpertRoute () {
             return this.$route.name === 'instance-editor-expert'
+        },
+        isInstanceOnNR5Plus () {
+            return isInstanceOnNR5Plus(this.instance)
         }
     },
     watch: {
diff --git a/frontend/src/pages/instance/Settings/Editor.vue b/frontend/src/pages/instance/Settings/Editor.vue
index 0104e72e2b..f64a567ad0 100644
--- a/frontend/src/pages/instance/Settings/Editor.vue
+++ b/frontend/src/pages/instance/Settings/Editor.vue
@@ -12,6 +12,7 @@ import { useRouter } from 'vue-router'
 import InstanceApi from '../../../api/instances.js'
 import usePermissions from '../../../composables/Permissions.js'
 import Dialog from '../../../services/dialog.js'
+import { isInstanceOnNR5Plus } from '../../../utils/instanceVersion'
 import TemplateSettingsEditor from '../../admin/Template/sections/Editor.vue'
 import {
     getObjectValue,
@@ -141,6 +142,16 @@ export default {
                         this.original.settings[field] = projectSettingsValue
                     }
                 })
+                // On NR5+ the runtime gate renders forge-light/forge-dark as `forge`.
+                // Normalize editable + original together so the dropdown matches without
+                // tripping the "changed" indicator. Lazy DB migration on next save.
+                if (isInstanceOnNR5Plus(this.project)) {
+                    const storedTheme = this.editable.settings.theme
+                    if (storedTheme === 'forge-light' || storedTheme === 'forge-dark') {
+                        this.editable.settings.theme = 'forge'
+                        this.original.settings.theme = 'forge'
+                    }
+                }
             }
         },
         async saveSettings () {
diff --git a/frontend/src/utils/instanceVersion.ts b/frontend/src/utils/instanceVersion.ts
new file mode 100644
index 0000000000..4ef99ee180
--- /dev/null
+++ b/frontend/src/utils/instanceVersion.ts
@@ -0,0 +1,20 @@
+import SemVer from 'semver'
+
+import { Maybe } from '@/types/common/types'
+
+/** Either an instance (Node-RED version under `meta.versions['node-red']`)
+ *  or a device (top-level `nodeRedVersion` field). */
+interface IInstanceVersionProps {
+    meta?: {
+        versions?: Record<string, string | undefined>
+    }
+    nodeRedVersion?: string | null
+}
+
+export function isInstanceOnNR5Plus (target: Maybe<IInstanceVersionProps> | undefined): boolean {
+    const nrVersion = target?.meta?.versions?.['node-red'] ?? target?.nodeRedVersion
+    if (!nrVersion) {
+        return false
+    }
+    return SemVer.satisfies(SemVer.coerce(nrVersion), '>=5.0.0')
+}
diff --git a/test/unit/frontend/utils/instanceVersion.spec.js b/test/unit/frontend/utils/instanceVersion.spec.js
new file mode 100644
index 0000000000..f0c24562f1
--- /dev/null
+++ b/test/unit/frontend/utils/instanceVersion.spec.js
@@ -0,0 +1,55 @@
+import { describe, expect, test } from 'vitest'
+
+import { isInstanceOnNR5Plus } from '../../../../frontend/src/utils/instanceVersion.ts'
+
+describe('isInstanceOnNR5Plus', () => {
+    test('returns false for null / undefined / empty objects', () => {
+        expect(isInstanceOnNR5Plus(null)).toBe(false)
+        expect(isInstanceOnNR5Plus(undefined)).toBe(false)
+        expect(isInstanceOnNR5Plus({})).toBe(false)
+        expect(isInstanceOnNR5Plus({ meta: {} })).toBe(false)
+        expect(isInstanceOnNR5Plus({ meta: { versions: {} } })).toBe(false)
+    })
+
+    test('returns false when the reported NR version is below 5', () => {
+        expect(isInstanceOnNR5Plus({ meta: { versions: { 'node-red': '4.1.8' } } })).toBe(false)
+        expect(isInstanceOnNR5Plus({ meta: { versions: { 'node-red': '3.1.0' } } })).toBe(false)
+        expect(isInstanceOnNR5Plus({ meta: { versions: { 'node-red': '4.99.99' } } })).toBe(false)
+    })
+
+    test('returns true for NR 5.x stable releases', () => {
+        expect(isInstanceOnNR5Plus({ meta: { versions: { 'node-red': '5.0.0' } } })).toBe(true)
+        expect(isInstanceOnNR5Plus({ meta: { versions: { 'node-red': '5.1.0' } } })).toBe(true)
+        expect(isInstanceOnNR5Plus({ meta: { versions: { 'node-red': '5.10.5' } } })).toBe(true)
+    })
+
+    test('returns true for NR 5.x prereleases (SemVer.coerce strips the tag)', () => {
+        expect(isInstanceOnNR5Plus({ meta: { versions: { 'node-red': '5.0.0-beta.6' } } })).toBe(true)
+        expect(isInstanceOnNR5Plus({ meta: { versions: { 'node-red': '5.0.0-rc.1' } } })).toBe(true)
+        expect(isInstanceOnNR5Plus({ meta: { versions: { 'node-red': '5.0.0-alpha.0' } } })).toBe(true)
+    })
+
+    test('returns true for future major versions', () => {
+        expect(isInstanceOnNR5Plus({ meta: { versions: { 'node-red': '6.0.0' } } })).toBe(true)
+        expect(isInstanceOnNR5Plus({ meta: { versions: { 'node-red': '10.2.3' } } })).toBe(true)
+    })
+
+    test('reads the device shape (top-level nodeRedVersion)', () => {
+        expect(isInstanceOnNR5Plus({ nodeRedVersion: '5.0.0-beta.6' })).toBe(true)
+        expect(isInstanceOnNR5Plus({ nodeRedVersion: '4.1.8' })).toBe(false)
+        expect(isInstanceOnNR5Plus({ nodeRedVersion: null })).toBe(false)
+        expect(isInstanceOnNR5Plus({ nodeRedVersion: '' })).toBe(false)
+    })
+
+    test('prefers instance shape over device shape when both are present', () => {
+        // Edge case: an object that has both fields. instance.meta.versions wins.
+        expect(isInstanceOnNR5Plus({
+            meta: { versions: { 'node-red': '5.0.0' } },
+            nodeRedVersion: '4.1.8'
+        })).toBe(true)
+        expect(isInstanceOnNR5Plus({
+            meta: { versions: { 'node-red': '4.1.8' } },
+            nodeRedVersion: '5.0.0'
+        })).toBe(false)
+    })
+})