diff --git a/src/app/[locale]/page.tsx b/src/app/[locale]/page.tsx
index 60d5337..e518b28 100644
--- a/src/app/[locale]/page.tsx
+++ b/src/app/[locale]/page.tsx
@@ -49,6 +49,7 @@ import { MemoryPanel } from "@/app/components/MemoryPanel";
 import { ScheduledTasksPanel } from "@/app/components/ScheduledTasksPanel";
 import { ThemeToggle } from "@/app/components/ThemeToggle";
 import { VersionBadge } from "@/app/components/VersionBadge";
+import { UpdateBanner } from "@/app/components/UpdateBanner";
 import { HealthIndicator } from "@/app/components/HealthIndicator";
 import { InspectorPanel } from "@/app/components/InspectorPanel";
 import { setThreadAutoApprove } from "@/lib/autoApprove";
@@ -481,6 +482,8 @@ function HomePageInner({ authEnabled, isAdmin }: HomePageInnerProps) {
           </div>
         </header>
 
+        <UpdateBanner />
+
         <div className="relative flex-1 overflow-hidden">
           {sidebar && isDesktopLayout === false && (
             <div className="absolute inset-0 z-40 flex md:hidden">
diff --git a/src/app/components/UpdateBanner.tsx b/src/app/components/UpdateBanner.tsx
new file mode 100644
index 0000000..ba153d0
--- /dev/null
+++ b/src/app/components/UpdateBanner.tsx
@@ -0,0 +1,101 @@
+"use client";
+
+import { useState } from "react";
+import useSWR from "swr";
+import { X } from "lucide-react";
+import { Button } from "@/components/ui/button";
+import type { SystemVersionInfo } from "@/app/api/system/version/route";
+import {
+  closeForSession,
+  dismissVersion,
+  isDismissed,
+  isSessionClosed,
+  loadDismissed,
+} from "@/lib/updatePrompt";
+
+async function fetchVersion(url: string): Promise<SystemVersionInfo> {
+  const res = await fetch(url, { cache: "no-store" });
+  if (!res.ok) throw new Error(`version check failed (${res.status})`);
+  return (await res.json()) as SystemVersionInfo;
+}
+
+export function UpdateBanner() {
+  const [, forceRender] = useState(0);
+  const backend = useSWR<SystemVersionInfo>("/api/system/version", fetchVersion, {
+    revalidateOnFocus: false,
+    shouldRetryOnError: false,
+  });
+  const frontend = useSWR<SystemVersionInfo>("/api/system/self-version", fetchVersion, {
+    revalidateOnFocus: false,
+    shouldRetryOnError: false,
+  });
+
+  if (typeof window === "undefined") return null;
+  if (isSessionClosed(sessionStorage)) return null;
+  const dismissed = loadDismissed(localStorage);
+
+  const rows: { key: "backend" | "frontend"; label: string; info: SystemVersionInfo }[] = [];
+  if (
+    backend.data?.has_update &&
+    !isDismissed(dismissed, "backend", backend.data.latest_version)
+  ) {
+    rows.push({ key: "backend", label: "Backend", info: backend.data });
+  }
+  if (
+    frontend.data?.has_update &&
+    !isDismissed(dismissed, "frontend", frontend.data.latest_version)
+  ) {
+    rows.push({ key: "frontend", label: "Web UI", info: frontend.data });
+  }
+  if (rows.length === 0) return null;
+
+  return (
+    <div className="flex items-start gap-3 border-b border-amber-500/30 bg-amber-500/10 px-4 py-2 text-sm">
+      <div className="flex-1 space-y-1">
+        {rows.map((r) => (
+          <p key={r.key}>
+            {r.label} <span className="font-mono">v{r.info.current_version}</span> →{" "}
+            <span className="font-mono font-medium">v{r.info.latest_version}</span> available.{" "}
+            {r.info.release_url && (
+              <a
+                className="underline"
+                href={r.info.release_url}
+                target="_blank"
+                rel="noreferrer"
+              >
+                Release notes
+              </a>
+            )}
+          </p>
+        ))}
+        <p className="text-xs text-muted-foreground">
+          Upgrading briefly interrupts the service and disconnects all connected sessions.
+        </p>
+      </div>
+      <Button variant="outline" size="sm" asChild>
+        <a href="#version">Review &amp; upgrade</a>
+      </Button>
+      <Button
+        variant="ghost"
+        size="sm"
+        onClick={() => {
+          for (const r of rows) dismissVersion(localStorage, r.key, r.info.latest_version);
+          forceRender((n) => n + 1);
+        }}
+      >
+        Ignore
+      </Button>
+      <Button
+        variant="ghost"
+        size="icon"
+        aria-label="Close"
+        onClick={() => {
+          closeForSession(sessionStorage);
+          forceRender((n) => n + 1);
+        }}
+      >
+        <X className="size-4" aria-hidden="true" />
+      </Button>
+    </div>
+  );
+}
diff --git a/src/app/components/VersionBadge.tsx b/src/app/components/VersionBadge.tsx
index ef23f66..97d7811 100644
--- a/src/app/components/VersionBadge.tsx
+++ b/src/app/components/VersionBadge.tsx
@@ -2,7 +2,7 @@
 
 import { useState } from "react";
 import useSWR from "swr";
-import { Copy, Download, ExternalLink, RefreshCw, Tag } from "lucide-react";
+import { ExternalLink, RefreshCw, RotateCcw, Tag, Upload } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import {
   DropdownMenu,
@@ -11,7 +11,7 @@ import {
 } from "@/components/ui/dropdown-menu";
 import { errorToast } from "@/lib/errorReporter";
 import type { SystemVersionInfo } from "@/app/api/system/version/route";
-import type { SystemVersionDownloadResult } from "@/app/api/system/version/download/route";
+import type { RollbackVersionsResult } from "@/app/api/system/rollback-versions/route";
 
 async function fetchVersion(url: string): Promise<SystemVersionInfo> {
   const res = await fetch(url, { cache: "no-store" });
@@ -26,23 +26,123 @@ async function fetchVersion(url: string): Promise<SystemVersionInfo> {
   return (await res.json()) as SystemVersionInfo;
 }
 
+type UpdateTargetKey = "backend" | "frontend";
+
 export function VersionBadge() {
   const [open, setOpen] = useState(false);
   const [refreshing, setRefreshing] = useState(false);
-  const [downloading, setDownloading] = useState(false);
-  const [downloaded, setDownloaded] =
-    useState<SystemVersionDownloadResult | null>(null);
+  const [updating, setUpdating] = useState(false);
+  const [updateStatus, setUpdateStatus] = useState<string | null>(null);
+  const [rollbackVersions, setRollbackVersions] = useState<
+    RollbackVersionsResult["versions"] | null
+  >(null);
   const { data, error, mutate } = useSWR<SystemVersionInfo>(
     "/api/system/version",
     fetchVersion,
     { revalidateOnFocus: false, shouldRetryOnError: false }
   );
+  const { data: selfData, mutate: mutateSelf } = useSWR<SystemVersionInfo>(
+    "/api/system/self-version",
+    fetchVersion,
+    { revalidateOnFocus: false, shouldRetryOnError: false }
+  );
+
+  const pollStatus = () => {
+    let failures = 0;
+    const timer = setInterval(async () => {
+      try {
+        const res = await fetch("/api/system/update/status", { cache: "no-store" });
+        if (!res.ok) throw new Error(String(res.status));
+        const body = await res.json();
+        failures = 0;
+        if (body.status === "success") {
+          clearInterval(timer);
+          setUpdateStatus("success — please reload the page");
+        } else if (body.status === "failed" || body.status === "installed_restart_failed") {
+          clearInterval(timer);
+          setUpdateStatus(`failed: ${body.message}`);
+        }
+      } catch {
+        // The service being upgraded is restarting; failed polls are expected.
+        failures += 1;
+        if (failures > 36) {
+          // ~3 minutes at a 5s interval
+          clearInterval(timer);
+          setUpdateStatus("not recovering — check the terminal logs");
+        }
+      }
+    }, 5000);
+  };
+
+  const startApply = async (url: string) => {
+    const res = await fetch(url, {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: "{}",
+    });
+    const body = await res.json().catch(() => null);
+    if (res.status === 202) {
+      setUpdateStatus("applying");
+      pollStatus();
+      return;
+    }
+    if (body?.code === "BREAKING_DB_CONFIRM_REQUIRED") {
+      if (window.confirm("This update contains breaking DB changes. Continue?")) {
+        await startApply(`${url}?confirm_breaking=true`);
+      }
+      return;
+    }
+    if (res.status === 200 && body?.status === "manual") {
+      setUpdateStatus(body.guidance ?? "manual update required");
+      return;
+    }
+    throw new Error(body?.message ?? body?.code ?? `Update failed (${res.status}).`);
+  };
+
+  const handleUpgrade = async (target: UpdateTargetKey) => {
+    setUpdating(true);
+    setUpdateStatus(null);
+    try {
+      await startApply(target === "backend" ? "/api/system/update" : "/api/system/self-update");
+    } catch (e) {
+      errorToast("version.update", e instanceof Error ? e.message : "Couldn't start the update.");
+    } finally {
+      setUpdating(false);
+    }
+  };
+
+  const handleRollback = async (version: string) => {
+    setUpdating(true);
+    setUpdateStatus(null);
+    try {
+      const res = await fetch("/api/system/update/rollback", {
+        method: "POST",
+        headers: { "Content-Type": "application/json" },
+        body: JSON.stringify({ version }),
+      });
+      const body = await res.json().catch(() => null);
+      if (res.status === 202) {
+        setUpdateStatus("applying");
+        pollStatus();
+        return;
+      }
+      throw new Error(body?.message ?? body?.code ?? `Rollback failed (${res.status}).`);
+    } catch (e) {
+      errorToast("version.rollback", e instanceof Error ? e.message : "Couldn't start the rollback.");
+    } finally {
+      setUpdating(false);
+    }
+  };
 
   const handleRefresh = async () => {
     setRefreshing(true);
     try {
-      const info = await fetchVersion("/api/system/version?force=true");
+      const [info, selfInfo] = await Promise.all([
+        fetchVersion("/api/system/version?force=true"),
+        fetchVersion("/api/system/self-version?force=true"),
+      ]);
       await mutate(info, { revalidate: false });
+      await mutateSelf(selfInfo, { revalidate: false });
     } catch (e) {
       errorToast(
         "version.refresh",
@@ -53,41 +153,28 @@ export function VersionBadge() {
     }
   };
 
-  const handleDownload = async () => {
-    setDownloading(true);
+  const loadRollbackVersions = async () => {
     try {
-      const res = await fetch("/api/system/version/download", {
-        method: "POST",
-        headers: { "Content-Type": "application/json" },
-        body: "{}",
-      });
-      const body = await res.json().catch(() => null);
-      if (!res.ok) {
-        throw new Error(
-          body && typeof body.message === "string"
-            ? body.message
-            : body && typeof body.error === "string"
-              ? body.error
-              : `Download failed (${res.status}).`
-        );
-      }
-      setDownloaded(body as SystemVersionDownloadResult);
-    } catch (e) {
-      errorToast(
-        "version.download",
-        e instanceof Error ? e.message : "Couldn't download the update."
-      );
-    } finally {
-      setDownloading(false);
+      const res = await fetch("/api/system/rollback-versions", { cache: "no-store" });
+      if (!res.ok) return;
+      const body = (await res.json()) as RollbackVersionsResult;
+      setRollbackVersions(body.versions);
+    } catch {
+      // The rollback list is best-effort; the upgrade path stays available.
     }
   };
 
   const handleOpenChange = (next: boolean) => {
     setOpen(next);
-    if (!next) setDownloaded(null);
+    if (next) {
+      setUpdateStatus(null);
+      setRollbackVersions(null);
+      if (data?.has_update) void loadRollbackVersions();
+    }
   };
 
   const hasUpdate = data?.has_update === true;
+  const selfHasUpdate = selfData?.has_update === true;
 
   return (
     <DropdownMenu modal={false} open={open} onOpenChange={handleOpenChange}>
@@ -96,16 +183,17 @@ export function VersionBadge() {
           variant="ghost"
           size="sm"
           aria-label="Version"
+          id="version"
           title={data ? `EvoScientist v${data.current_version}` : "Version"}
           className={`relative h-8 gap-1 px-2 text-xs ${
-            hasUpdate
+            hasUpdate || selfHasUpdate
               ? "bg-amber-500/15 text-amber-600 hover:bg-amber-500/25 dark:text-amber-400"
               : "text-muted-foreground"
           }`}
         >
           <Tag className="size-3.5" aria-hidden="true" />
           {data ? `v${data.current_version}` : "…"}
-          {hasUpdate && (
+          {(hasUpdate || selfHasUpdate) && (
             <span className="absolute -right-0.5 -top-0.5 flex size-2">
               <span className="absolute inline-flex size-full animate-ping rounded-full bg-amber-500 opacity-75" />
               <span className="relative inline-flex size-2 rounded-full bg-amber-500" />
@@ -114,88 +202,108 @@ export function VersionBadge() {
         </Button>
       </DropdownMenuTrigger>
       <DropdownMenuContent align="end" className="w-80 p-0">
-        <div className="border-b border-border px-3 py-2 text-sm font-medium">
-          Version
-        </div>
+        <div className="border-b border-border px-3 py-2 text-sm font-medium">Version</div>
         {error && !data ? (
           <p className="px-3 py-6 text-center text-sm text-muted-foreground">
             Couldn&apos;t load version info.
           </p>
         ) : !data ? (
-          <p className="px-3 py-6 text-center text-sm text-muted-foreground">
-            Loading...
-          </p>
+          <p className="px-3 py-6 text-center text-sm text-muted-foreground">Loading...</p>
         ) : (
-          <div className="space-y-2 px-3 py-3 text-sm">
-            <div className="flex items-baseline justify-between gap-2">
-              <span className="text-muted-foreground">Installed</span>
-              <span className="font-mono">v{data.current_version}</span>
-            </div>
-            <div className="flex items-baseline justify-between gap-2">
-              <span className="text-muted-foreground">Latest</span>
-              <span
-                className={`font-mono ${
-                  hasUpdate ? "font-medium text-amber-600 dark:text-amber-400" : ""
-                }`}
-              >
-                v{data.latest_version}
-              </span>
-            </div>
-            {hasUpdate && (
-              <p className="rounded-md bg-amber-500/10 px-2 py-1.5 text-xs text-amber-700 dark:text-amber-300">
-                A new version of EvoScientist is available.
+          <div className="space-y-3 px-3 py-3 text-sm">
+            <div className="space-y-2">
+              <p className="text-xs font-medium uppercase tracking-wide text-muted-foreground">
+                Backend
               </p>
-            )}
-            {data.warning && (
-              <p className="text-xs text-muted-foreground">
-                Last check failed: {data.warning}
-              </p>
-            )}
-            {hasUpdate && !downloaded && (
-              <Button
-                variant="outline"
-                size="sm"
-                className="w-full"
-                disabled={downloading}
-                onClick={() => void handleDownload()}
-              >
-                <Download
-                  className={`mr-1 size-3.5 ${downloading ? "animate-bounce" : ""}`}
-                  aria-hidden="true"
-                />
-                {downloading
-                  ? "Downloading..."
-                  : `Download v${data.latest_version}`}
-              </Button>
-            )}
-            {downloaded && (
-              <div className="rounded-md border border-border p-2 text-xs">
-                <p className="break-all font-mono text-muted-foreground">
-                  {downloaded.path}
-                </p>
-                <div className="mt-1 flex items-start gap-1">
-                  <code className="flex-1 break-all rounded bg-muted px-1.5 py-1">
-                    {downloaded.suggested_command}
-                  </code>
-                  <Button
-                    variant="ghost"
-                    size="icon"
-                    className="size-6 shrink-0"
-                    aria-label="Copy install command"
-                    title="Copy install command"
-                    onClick={() =>
-                      void navigator.clipboard.writeText(
-                        downloaded.suggested_command
-                      )
-                    }
-                  >
-                    <Copy className="size-3.5" aria-hidden="true" />
-                  </Button>
-                </div>
-                <p className="mt-1 text-muted-foreground">
-                  Run this on the backend host, then restart it.
-                </p>
+              <div className="flex items-baseline justify-between gap-2">
+                <span className="text-muted-foreground">Installed</span>
+                <span className="font-mono">v{data.current_version}</span>
               </div>
+              <div className="flex items-baseline justify-between gap-2">
+                <span className="text-muted-foreground">Latest</span>
+                <span
+                  className={`font-mono ${
+                    hasUpdate ? "font-medium text-amber-600 dark:text-amber-400" : ""
+                  }`}
+                >
+                  v{data.latest_version}
+                </span>
+              </div>
+              {data.warning && (
+                <p className="text-xs text-muted-foreground">
+                  Last check failed: {data.warning}
+                </p>
+              )}
+              {hasUpdate && (
+                <Button
+                  variant="outline"
+                  size="sm"
+                  className="w-full"
+                  disabled={updating}
+                  onClick={() => void handleUpgrade("backend")}
+                >
+                  <Upload className="mr-1 size-3.5" aria-hidden="true" />
+                  {updating ? "Starting..." : `Upgrade to v${data.latest_version}`}
+                </Button>
+              )}
+              {rollbackVersions && rollbackVersions.length > 0 && (
+                <div className="flex items-center gap-1 text-xs">
+                  <RotateCcw className="size-3 text-muted-foreground" aria-hidden="true" />
+                  <span className="text-muted-foreground">Roll back:</span>
+                  {rollbackVersions.map((v) => (
+                    <Button
+                      key={v.version}
+                      variant="ghost"
+                      size="sm"
+                      className="h-6 px-1.5 font-mono text-xs"
+                      disabled={updating}
+                      onClick={() => void handleRollback(v.version)}
+                    >
+                      v{v.version}
+                    </Button>
+                  ))}
+                </div>
+              )}
+            </div>
+            {selfData && (
+              <div className="space-y-2 border-t border-border pt-2">
+                <p className="text-xs font-medium uppercase tracking-wide text-muted-foreground">
+                  Web UI
+                </p>
+                <div className="flex items-baseline justify-between gap-2">
+                  <span className="text-muted-foreground">Installed</span>
+                  <span className="font-mono">v{selfData.current_version}</span>
+                </div>
+                <div className="flex items-baseline justify-between gap-2">
+                  <span className="text-muted-foreground">Latest</span>
+                  <span
+                    className={`font-mono ${
+                      selfHasUpdate ? "font-medium text-amber-600 dark:text-amber-400" : ""
+                    }`}
+                  >
+                    v{selfData.latest_version}
+                  </span>
+                </div>
+                {selfHasUpdate && (
+                  <Button
+                    variant="outline"
+                    size="sm"
+                    className="w-full"
+                    disabled={updating}
+                    onClick={() => void handleUpgrade("frontend")}
+                  >
+                    <Upload className="mr-1 size-3.5" aria-hidden="true" />
+                    {updating ? "Starting..." : `Upgrade Web UI to v${selfData.latest_version}`}
+                  </Button>
+                )}
+              </div>
+            )}
+            {updateStatus && (
+              <p className="rounded-md bg-muted px-2 py-1.5 text-xs text-muted-foreground">
+                {updateStatus === "applying"
+                  ? "Updating — the service will briefly interrupt; this page may lose connection."
+                  : updateStatus}
+              </p>
             )}
           </div>
         )}
diff --git a/src/lib/updatePrompt.test.ts b/src/lib/updatePrompt.test.ts
new file mode 100644
index 0000000..08e4161
--- /dev/null
+++ b/src/lib/updatePrompt.test.ts
@@ -0,0 +1,46 @@
+import { describe, expect, it } from "vitest";
+import {
+  closeForSession,
+  dismissVersion,
+  isDismissed,
+  isSessionClosed,
+  loadDismissed,
+} from "./updatePrompt";
+
+function fakeStorage(): Storage {
+  const map = new Map<string, string>();
+  return {
+    getItem: (k) => map.get(k) ?? null,
+    setItem: (k, v) => void map.set(k, v),
+    removeItem: (k) => void map.delete(k),
+    clear: () => map.clear(),
+    key: () => null,
+    get length() {
+      return map.size;
+    },
+  } as Storage;
+}
+
+describe("updatePrompt storage", () => {
+  it("dismissed version stays dismissed until a newer one appears", () => {
+    const s = fakeStorage();
+    dismissVersion(s, "backend", "0.3.0");
+    const d = loadDismissed(s);
+    expect(isDismissed(d, "backend", "0.3.0")).toBe(true);
+    expect(isDismissed(d, "backend", "0.3.1")).toBe(false);
+    expect(isDismissed(d, "frontend", "0.3.0")).toBe(false);
+  });
+
+  it("session close is separate from dismiss", () => {
+    const s = fakeStorage();
+    expect(isSessionClosed(s)).toBe(false);
+    closeForSession(s);
+    expect(isSessionClosed(s)).toBe(true);
+  });
+
+  it("corrupt storage falls back to empty", () => {
+    const s = fakeStorage();
+    s.setItem("dismissedVersions", "{not json");
+    expect(loadDismissed(s)).toEqual({});
+  });
+});
diff --git a/src/lib/updatePrompt.ts b/src/lib/updatePrompt.ts
new file mode 100644
index 0000000..438b77d
--- /dev/null
+++ b/src/lib/updatePrompt.ts
@@ -0,0 +1,38 @@
+const DISMISS_KEY = "dismissedVersions";
+const SESSION_KEY = "updateBannerClosed";
+
+export type UpdateTarget = "backend" | "frontend";
+export type DismissedVersions = Partial<Record<UpdateTarget, string>>;
+
+export function loadDismissed(storage: Storage): DismissedVersions {
+  try {
+    const raw = storage.getItem(DISMISS_KEY);
+    if (!raw) return {};
+    const parsed: unknown = JSON.parse(raw);
+    if (parsed && typeof parsed === "object") return parsed as DismissedVersions;
+    return {};
+  } catch {
+    return {};
+  }
+}
+
+export function dismissVersion(storage: Storage, key: UpdateTarget, version: string): void {
+  const next = { ...loadDismissed(storage), [key]: version };
+  storage.setItem(DISMISS_KEY, JSON.stringify(next));
+}
+
+export function isDismissed(
+  dismissed: DismissedVersions,
+  key: UpdateTarget,
+  version: string
+): boolean {
+  return dismissed[key] === version;
+}
+
+export function isSessionClosed(storage: Storage): boolean {
+  return storage.getItem(SESSION_KEY) === "1";
+}
+
+export function closeForSession(storage: Storage): void {
+  storage.setItem(SESSION_KEY, "1");
+}