diff --git a/server/main.go b/server/main.go
index 9452812..ec8636c 100644
--- a/server/main.go
+++ b/server/main.go
@@ -517,7 +517,7 @@ func newSWVersion(dir string) *swVersion {
 	// circular and it never changes except when we edit it here.
 	return &swVersion{
 		dir:   dir,
-		files: []string{"index.html", "style.css", "app.js", "manifest.json", "icon.svg"},
+		files: []string{"index.html", "style.css", "app.js", "manifest.json", "icon.svg", "changelog.json"},
 	}
 }
 
diff --git a/src/app.js b/src/app.js
index 85f2250..3a47709 100644
--- a/src/app.js
+++ b/src/app.js
@@ -2149,9 +2149,44 @@
       location.reload();
     });
 
+    // What the waiting build changes compared to the running one. The plain
+    // URL is answered by the *old* controlling worker cache-first, i.e. the
+    // loaded build's changelog; the cache-busting query misses every SW cache
+    // and hits the network, i.e. the new build's changelog. Entries in the
+    // fresh copy that the cached one lacks are exactly "new since this build".
+    async function changelogDiff() {
+      const load = async (url) => {
+        try {
+          const res = await fetch(url);
+          if (!res.ok) return null;
+          const body = await res.json();
+          return Array.isArray(body) ? body : null;
+        } catch {
+          return null;
+        }
+      };
+      const current = await load("changelog.json");
+      const fresh   = await load(`changelog.json?v=${Date.now()}`);
+      if (!fresh) return [];
+      const seen = new Set((current || []).map(e => e && e.text));
+      return fresh.filter(e => e && e.text && !seen.has(e.text));
+    }
+
     function showUpdateBanner(worker) {
       waitingWorker = worker;
       updateBanner.hidden = false;
+      const list = document.getElementById("update-changelog");
+      list.hidden = true;
+      list.innerHTML = "";
+      changelogDiff().then(entries => {
+        if (entries.length === 0) return;
+        for (const e of entries.slice(0, 6)) {
+          const li = document.createElement("li");
+          li.textContent = e.text;
+          list.appendChild(li);
+        }
+        list.hidden = false;
+      });
     }
 
     updateReload.addEventListener("click", () => {
diff --git a/src/changelog.json b/src/changelog.json
new file mode 100644
index 0000000..a7904ce
--- /dev/null
+++ b/src/changelog.json
@@ -0,0 +1,5 @@
+[
+  { "date": "2026-07-12", "text": "The update banner now lists what changed in the new version" },
+  { "date": "2026-07-12", "text": "Fixed adding an exercise on iPhone: stale app updates, and the keyboard's Go key discarding the input" },
+  { "date": "2026-07-12", "text": "Training: define exercises with how-to reminders, log sessions in one tap, and follow a 14-day consistency view" }
+]
diff --git a/src/index.html b/src/index.html
index a4db13b..94779ad 100644
--- a/src/index.html
+++ b/src/index.html
@@ -25,11 +25,16 @@
          it and refreshes onto the new assets; "Later" dismisses until next time.
          Suppressed on the very first install (see app.js). -->
     <div id="update-banner" class="update-banner" hidden role="status" aria-live="polite">
-      <span class="update-banner-msg">A new version is available</span>
-      <span class="update-banner-actions">
-        <button type="button" id="update-reload" class="update-banner-btn">Reload</button>
-        <button type="button" id="update-later" class="update-banner-btn ghostish">Later</button>
-      </span>
+      <div class="update-banner-row">
+        <span class="update-banner-msg">A new version is available</span>
+        <span class="update-banner-actions">
+          <button type="button" id="update-reload" class="update-banner-btn">Reload</button>
+          <button type="button" id="update-later" class="update-banner-btn ghostish">Later</button>
+        </span>
+      </div>
+      <!-- What the waiting build adds over the running one; filled by app.js
+           from the diff between the cached and the fresh changelog.json. -->
+      <ul id="update-changelog" class="update-changelog" hidden></ul>
     </div>
 
     <!-- Login / register gate. Shown until the session check succeeds; the app
diff --git a/src/style.css b/src/style.css
index 9ec0e6f..5dfd4fc 100644
--- a/src/style.css
+++ b/src/style.css
@@ -673,17 +673,28 @@ input.switch:checked::after { transform: translateX(18px); }
   left: 0;
   right: 0;
   z-index: 70;
-  display: flex;
-  align-items: center;
-  justify-content: center;
-  gap: 12px;
-  flex-wrap: wrap;
   padding: calc(10px + env(safe-area-inset-top, 0)) 16px 10px;
   background: var(--accent);
   color: #fff;
   box-shadow: var(--shadow);
 }
 .update-banner[hidden] { display: none; }
+.update-banner-row {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  gap: 12px;
+  flex-wrap: wrap;
+}
+.update-changelog {
+  max-width: 480px;
+  margin: 6px auto 0;
+  padding: 0 0 0 18px;
+  font-size: 0.8rem;
+  line-height: 1.45;
+  opacity: 0.92;
+}
+.update-changelog[hidden] { display: none; }
 .update-banner-msg { font-size: 0.9rem; font-weight: 600; }
 .update-banner-actions { display: flex; gap: 8px; }
 .update-banner-btn {
diff --git a/src/sw.js b/src/sw.js
index b3a05c8..98af92e 100644
--- a/src/sw.js
+++ b/src/sw.js
@@ -13,6 +13,7 @@ const ASSETS = [
   "./app.js",
   "./manifest.json",
   "./icon.svg",
+  "./changelog.json",
 ];
 
 self.addEventListener("install", (event) => {