1 files changed, 69 insertions, 1 deletions

diff --git a/packages/meshbay-client/src/main.js b/packages/meshbay-client/src/main.js
index 9ff0069..ab579a1 100644
--- a/packages/meshbay-client/src/main.js
+++ b/packages/meshbay-client/src/main.js
@@ -1701,6 +1701,71 @@ function describeUnreachable(url, error) {
   return `Could not reach ${url}: ${detail}`;
 }
 
+// ── The version gate ────────────────────────────────────────────────────────
+
+/** Compare two dotted versions. -1, 0 or 1; unreadable sorts as equal. */
+function compareVersions(a, b) {
+  const parse = (v) => String(v || '').split('.').map((n) => parseInt(n, 10));
+  const [x, y] = [parse(a), parse(b)];
+  if (x.some(Number.isNaN) || y.some(Number.isNaN)) return 0;
+  for (let i = 0; i < Math.max(x.length, y.length); i++) {
+    const d = (x[i] || 0) - (y[i] || 0);
+    if (d) return d < 0 ? -1 : 1;
+  }
+  return 0;
+}
+
+/**
+ * Refuse to start when this build is older than the hub will talk to.
+ *
+ * The reason this exists rather than letting the handshake do it: the SPA is
+ * served by the hub and picks up a new client on reload, but **this
+ * application ships its own interface**. On the MNP 3.0 flag day an
+ * un-updated one can still sign in, still list groups, and then fail every
+ * connection with `version_too_old` — a refusal in a protocol vocabulary,
+ * surfacing as a node that will not talk, with nothing anyone can act on.
+ *
+ * So the question is asked once, up front, of `/v1/hub/version`, which has
+ * carried `client.minimum` since before there was a client to check it.
+ *
+ * **Unreachable is not too old.** A hub that is down, a laptop with no network,
+ * a captive portal: none of those are a reason to refuse to open the
+ * application, and treating them as one would make an offline start impossible
+ * for ever. Only a definite answer, saying in so many words that this version
+ * is below the minimum, stops anything.
+ */
+async function refuseIfTooOld() {
+  const base = String(config.hubBase || '').replace(/\/+$/, '');
+  if (!base) return false;   // First run: there is no hub to ask yet.
+  let info;
+  try {
+    const r = await fetch(`${base}/v1/hub/version`,
+                          { signal: AbortSignal.timeout(10000) });
+    if (!r.ok) return false;
+    info = await r.json();
+  } catch {
+    return false;
+  }
+  const minimum = info && info.client && info.client.minimum;
+  if (!minimum) return false;
+  const mine = app.getVersion();
+  if (compareVersions(mine, minimum) >= 0) return false;
+
+  const { response } = await dialog.showMessageBox({
+    type: 'warning',
+    title: 'Update required',
+    message: 'This version of MeshBay can no longer connect',
+    detail: `This application is version ${mine}, and ${base} now requires `
+      + `${minimum} or later.\n\nDownload the current version and install it `
+      + 'over this one — your groups, keys and settings are kept.',
+    buttons: ['Download the update', 'Quit'],
+    defaultId: 0,
+    cancelId: 1,
+  });
+  if (response === 0) await shell.openExternal(base);
+  return true;
+}
+
 // ── Lifecycle ───────────────────────────────────────────────────────────────
 
 // One instance. Two would fight over the config file and the secrets blob, and
@@ -1712,7 +1777,10 @@ if (!app.requestSingleInstanceLock()) {
     showFromTray();
   });
 
-  app.whenReady().then(() => {
+  app.whenReady().then(async () => {
+    // Before anything else is built. A window that opens and then cannot
+    // connect is the failure this replaces.
+    if (await refuseIfTooOld()) { app.quit(); return; }
     registerUiProtocol();
     // Before ensureTray: buildTrayMenu reads `nodeService`, which registerBridge
     // assigns, so creating the tray after it means the Start/Stop entry is on