diff --git a/.github/workflows/release-stable.yml b/.github/workflows/release-stable.yml
index 0a85bd2b..9a97f18b 100644
--- a/.github/workflows/release-stable.yml
+++ b/.github/workflows/release-stable.yml
@@ -22,15 +22,32 @@ jobs:
     runs-on: ubuntu-latest
     outputs:
       version: ${{ steps.ver.outputs.version }}
+      display_version: ${{ steps.ver.outputs.display_version }}
       tag: ${{ steps.ver.outputs.tag }}
     steps:
       - id: ver
         shell: bash
         run: |
-          VERSION="${GITHUB_REF_NAME#stable-v}"
-          echo "version=$VERSION" >> "$GITHUB_OUTPUT"
-          echo "tag=${GITHUB_REF_NAME}" >> "$GITHUB_OUTPUT"
-          echo "### Stable version: \`$VERSION\`" >> "$GITHUB_STEP_SUMMARY"
+          python3 <<'PY' > version.env
+          import os
+          import re
+          from datetime import date
+
+          tag = os.environ["GITHUB_REF_NAME"]
+          version = tag.removeprefix("stable-v")
+          match = re.fullmatch(r"(\d{4})\.(\d{1,2})\.(\d{1,2})", version)
+          if not match:
+              raise SystemExit(f"Stable tags must use stable-vYYYY.M.D, got {tag}")
+
+          date(*map(int, match.groups()))
+          print(f"version={version}")
+          print(f"display_version={version}")
+          print(f"tag={tag}")
+          PY
+
+          cat version.env >> "$GITHUB_OUTPUT"
+          DISPLAY_VERSION=$(grep '^display_version=' version.env | cut -d= -f2-)
+          echo "### Stable version: \`$DISPLAY_VERSION\`" >> "$GITHUB_STEP_SUMMARY"
 
   # ─────────────────────────────────────────────────────────────
   # Phase 2: Build each architecture in parallel
@@ -211,7 +228,7 @@ jobs:
         uses: softprops/action-gh-release@v2
         with:
           tag_name: ${{ needs.version.outputs.tag }}
-          name: Tolaria ${{ needs.version.outputs.version }}
+          name: Tolaria ${{ needs.version.outputs.display_version }}
           body_path: release_notes.md
           draft: false
           prerelease: false
@@ -275,7 +292,7 @@ jobs:
           </head>
           <body>
             <h1>Tolaria Release History</h1>
-            <p class="subtitle">Alpha builds update on every push to main. Stable builds appear when a stable-vX.Y.Z tag is promoted.</p>
+            <p class="subtitle">Alpha builds update on every push to main. Stable builds appear when a stable-vYYYY.M.D tag is promoted.</p>
             <div id="releases"></div>
             <script>
               fetch('releases.json').then(r=>r.json()).then(releases=>{
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index cf610979..bd4e400b 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -16,13 +16,14 @@ concurrency:
 jobs:
   # ─────────────────────────────────────────────────────────────
   # Phase 1: Compute the alpha version string once
-  # Alpha builds are prereleases of the next stable patch version.
+  # Alpha builds use calendar semver and stay newer than the latest stable tag.
   # ─────────────────────────────────────────────────────────────
   version:
     name: Compute alpha version
     runs-on: ubuntu-latest
     outputs:
       version: ${{ steps.ver.outputs.version }}
+      display_version: ${{ steps.ver.outputs.display_version }}
       tag: ${{ steps.ver.outputs.tag }}
     steps:
       - uses: actions/checkout@v4
@@ -32,22 +33,63 @@ jobs:
       - id: ver
         shell: bash
         run: |
-          LAST_STABLE_TAG=$(git tag --list 'stable-v*' --sort=-version:refname | head -n 1)
-          if [ -z "$LAST_STABLE_TAG" ]; then
-            BASE_VERSION="0.1.0"
-          else
-            BASE_VERSION="${LAST_STABLE_TAG#stable-v}"
-          fi
+          python3 <<'PY' > version.env
+          import re
+          import subprocess
+          from datetime import datetime, timedelta, timezone
 
-          IFS='.' read -r MAJOR MINOR PATCH <<EOF
-          $BASE_VERSION
-          EOF
-          NEXT_PATCH_VERSION="${MAJOR}.${MINOR}.$((PATCH + 1))"
+          def lines(command: list[str]) -> list[str]:
+              output = subprocess.check_output(command, text=True).strip()
+              return [line for line in output.splitlines() if line]
 
-          VERSION="${NEXT_PATCH_VERSION}-alpha.$(date -u +%Y%m%d%H%M).${GITHUB_RUN_NUMBER}"
-          echo "version=$VERSION" >> "$GITHUB_OUTPUT"
-          echo "tag=alpha-v$VERSION" >> "$GITHUB_OUTPUT"
-          echo "### Alpha version: \`$VERSION\`" >> "$GITHUB_STEP_SUMMARY"
+          existing_tags = [
+              tag for tag in lines(["git", "tag", "--points-at", "HEAD"])
+              if tag.startswith("alpha-v")
+          ]
+
+          if existing_tags:
+              tag = existing_tags[0]
+              version = tag.removeprefix("alpha-v")
+          else:
+              today = datetime.now(timezone.utc).date()
+              stable_date = None
+              stable_pattern = re.compile(r"^stable-v(\d{4})\.(\d{1,2})\.(\d{1,2})$")
+
+              for stable_tag in lines(["git", "tag", "--list", "stable-v*", "--sort=-version:refname"]):
+                  match = stable_pattern.fullmatch(stable_tag)
+                  if not match:
+                      continue
+
+                  year, month, day = map(int, match.groups())
+                  try:
+                      stable_date = datetime(year, month, day, tzinfo=timezone.utc).date()
+                  except ValueError:
+                      continue
+                  break
+
+              alpha_date = today if stable_date is None or today > stable_date else stable_date + timedelta(days=1)
+              calendar_version = f"{alpha_date.year}.{alpha_date.month}.{alpha_date.day}"
+              sequence = len(lines(["git", "tag", "--list", f"alpha-v{calendar_version}-alpha.*"])) + 1
+
+              version = f"{calendar_version}-alpha.{sequence}"
+              tag = f"alpha-v{version}"
+
+          display_match = re.fullmatch(r"(\d{4})\.(\d{1,2})\.(\d{1,2})-alpha\.(\d+)", version)
+          display_version = (
+              f"Alpha {int(display_match.group(1))}.{int(display_match.group(2))}.{int(display_match.group(3))}.{int(display_match.group(4))}"
+              if display_match
+              else version
+          )
+
+          print(f"version={version}")
+          print(f"display_version={display_version}")
+          print(f"tag={tag}")
+          PY
+
+          cat version.env >> "$GITHUB_OUTPUT"
+          VERSION=$(grep '^version=' version.env | cut -d= -f2-)
+          DISPLAY_VERSION=$(grep '^display_version=' version.env | cut -d= -f2-)
+          echo "### Alpha version: \`$DISPLAY_VERSION\` (\`$VERSION\`)" >> "$GITHUB_STEP_SUMMARY"
 
   # ─────────────────────────────────────────────────────────────
   # Phase 2: Build each architecture in parallel
@@ -225,7 +267,7 @@ jobs:
         uses: softprops/action-gh-release@v2
         with:
           tag_name: ${{ needs.version.outputs.tag }}
-          name: Tolaria ${{ needs.version.outputs.version }} (Alpha)
+          name: Tolaria ${{ needs.version.outputs.display_version }}
           body_path: release_notes.md
           draft: false
           prerelease: true
@@ -288,7 +330,7 @@ jobs:
           </head>
           <body>
             <h1>Tolaria Release History</h1>
-            <p class="subtitle">Alpha builds update on every push to main. Stable builds appear when a stable-vX.Y.Z tag is promoted.</p>
+            <p class="subtitle">Alpha builds update on every push to main. Stable builds appear when a stable-vYYYY.M.D tag is promoted.</p>
             <div id="releases"></div>
             <script>
               fetch('releases.json').then(r=>r.json()).then(releases=>{
diff --git a/docs/ABSTRACTIONS.md b/docs/ABSTRACTIONS.md
index 12c0685d..75b9a1f1 100644
--- a/docs/ABSTRACTIONS.md
+++ b/docs/ABSTRACTIONS.md
@@ -621,12 +621,13 @@ Managed by `useSettings` hook and `SettingsPanel` component. `default_ai_agent`
 
 ### Rust
 - **`src-tauri/src/app_updater.rs`** — Chooses the correct update endpoint (`alpha/latest.json` or `stable/latest.json`) and adapts Tauri updater results into frontend-friendly payloads.
+- **`src-tauri/src/commands/version.rs`** — Formats app build/version labels for the status bar, including calendar alpha labels and legacy release compatibility.
 
 ### Tauri Commands
 - **`check_for_app_update`** — Channel-aware update manifest lookup.
 - **`download_and_install_app_update`** — Channel-aware download/install with streamed progress events.
 
 ### CI/CD
-- **`.github/workflows/release.yml`** — Alpha prereleases from every push to `main`. Publishes `alpha/latest.json` and refreshes the legacy `latest.json` / `latest-canary.json` aliases to the alpha feed.
-- **`.github/workflows/release-stable.yml`** — Stable releases from `stable-v*` tags. Publishes `stable/latest.json`.
+- **`.github/workflows/release.yml`** — Alpha prereleases from every push to `main` using calendar-semver technical versions (`YYYY.M.D-alpha.N`) and clean `Alpha YYYY.M.D.N` release names. Publishes `alpha/latest.json` and refreshes the legacy `latest.json` / `latest-canary.json` aliases to the alpha feed.
+- **`.github/workflows/release-stable.yml`** — Stable releases from `stable-vYYYY.M.D` tags. Publishes `stable/latest.json`.
 - **Beta cohorts** are handled in PostHog targeting only. There is no beta updater feed.
diff --git a/docs/ARCHITECTURE.md b/docs/ARCHITECTURE.md
index ecada44f..06e2063f 100644
--- a/docs/ARCHITECTURE.md
+++ b/docs/ARCHITECTURE.md
@@ -689,7 +689,7 @@ The vault backend (`src-tauri/src/vault/`) is split into focused submodules:
 | `trigger_menu_command` | Emit a native menu command ID for deterministic shortcut QA |
 | `update_current_window_min_size` | Update the active Tauri window's minimum size and optionally grow it to fit restored panes |
 
-`get_build_number` feeds the bottom status bar label. It preserves legacy `bNNN` date-build labels, renders local `0.1.0` / `0.0.0` builds as `dev`, and formats semver alpha prereleases as `alpha <version>` so signed alpha builds never fall back to `?`.
+`get_build_number` feeds the bottom status bar label. It preserves legacy `bNNN` date-build labels, renders local `0.1.0` / `0.0.0` builds as `dev`, formats calendar alpha builds as `Alpha YYYY.M.D.N`, strips any calendar `-stable.N` suffix back to `YYYY.M.D`, and keeps legacy semver releases readable instead of falling back to `?`.
 
 ## Mock Layer
 
@@ -766,14 +766,15 @@ Every push to `main` triggers `.github/workflows/release.yml`:
 
 ```
 push to main
-  → version job: read latest stable-vX.Y.Z tag
-  → compute next patch prerelease X.Y.(Z+1)-alpha.UTCSTAMP.RUN_NUMBER
+  → version job: compute calendar alpha version YYYY.M.D-alpha.N
+      → use today's UTC date unless the latest stable-vYYYY.M.D tag already uses today
+      → if stable already uses today, advance alpha to the next calendar day so semver still increases
   → build job:
-      → pnpm install, stamp version, pnpm build, tauri build --target aarch64-apple-darwin
-      → upload signed .app.tar.gz + .sig and .dmg artifacts
+      → pnpm install, stamp version, pnpm build, tauri build --target aarch64-apple-darwin --bundles app
+      → upload signed .app.tar.gz + .sig updater artifacts
   → release job:
       → generate alpha-latest.json
-      → publish GitHub prerelease alpha-v<version>
+      → publish GitHub prerelease alpha-v<version> named Tolaria Alpha YYYY.M.D.N
   → pages job:
       → build static HTML release history page
       → publish alpha/latest.json
@@ -785,14 +786,14 @@ push to main
 Stable promotions trigger `.github/workflows/release-stable.yml`:
 
 ```
-push stable-vX.Y.Z tag
-  → version job: use X.Y.Z from the tag
+push stable-vYYYY.M.D tag
+  → version job: validate YYYY.M.D from the tag
   → build job:
       → pnpm install, stamp version, pnpm build, tauri build --target aarch64-apple-darwin
       → upload signed .app.tar.gz + .sig and .dmg artifacts
   → release job:
       → generate stable-latest.json
-      → publish GitHub release Tolaria X.Y.Z
+      → publish GitHub release Tolaria YYYY.M.D
   → pages job:
       → publish stable/latest.json
       → preserve alpha/latest.json
@@ -801,10 +802,11 @@ push stable-vX.Y.Z tag
 
 ### Versioning
 
-- Stable promotions use git tags in the form `stable-vX.Y.Z`.
-- Alpha builds are prereleases of the next stable patch version, for example stable `1.2.3` → alpha `1.2.4-alpha.202604122135.7`.
+- Stable promotions use git tags in the form `stable-vYYYY.M.D` and stamp the technical version `YYYY.M.D`.
+- Alpha builds stamp the technical version `YYYY.M.D-alpha.N` and display it as `Alpha YYYY.M.D.N`.
+- If the latest stable tag already uses today's date, alpha advances to the next calendar day before assigning `-alpha.N` so Alpha remains semver-newer than Stable across channel switches.
 - The workflows stamp the computed version into `tauri.conf.json` and `Cargo.toml` at build time.
-- This keeps semver monotonic when a user switches between Stable and Alpha.
+- This keeps display strings clean while preserving semver monotonicity when a user switches between Stable and Alpha.
 
 ### In-App Updates
 
diff --git a/docs/adr/0066-calendar-semver-versioning-for-alpha-and-stable-releases.md b/docs/adr/0066-calendar-semver-versioning-for-alpha-and-stable-releases.md
new file mode 100644
index 00000000..b18b1a5d
--- /dev/null
+++ b/docs/adr/0066-calendar-semver-versioning-for-alpha-and-stable-releases.md
@@ -0,0 +1,37 @@
+---
+type: ADR
+id: "0066"
+title: "Calendar-semver versioning for alpha and stable releases"
+status: active
+date: 2026-04-16
+supersedes: "0057"
+---
+
+## Context
+
+ADR-0057 kept Tolaria on two updater channels and used "next stable patch" semver for alpha builds. That preserved ordering, but it no longer matched the agreed product naming:
+
+- Alpha should display as `Alpha YYYY.M.D.N`
+- Alpha should ship the technical version `YYYY.M.D-alpha.N`
+- Stable should ship and display as `YYYY.M.D`
+
+The naming change still needs to stay semver-safe when users switch between Stable and Alpha. A pure same-day calendar alpha would become older than a same-day stable promotion, so the workflow needs a monotonicity guard in addition to cleaner display strings.
+
+## Decision
+
+**Tolaria keeps exactly two updater channels (`stable` and `alpha`), but both now use calendar-semver release numbers.** Stable promotions use `stable-vYYYY.M.D` tags and stamp the technical version `YYYY.M.D`. Every push to `main` publishes an alpha build with technical version `YYYY.M.D-alpha.N` and display label `Alpha YYYY.M.D.N`.
+
+If the latest stable tag already uses the current UTC calendar date, the alpha workflow advances to the next calendar day before assigning `-alpha.N`. That keeps alpha semver-newer than the most recent stable build even after a same-day promotion.
+
+## Options considered
+
+- **Calendar semver with a next-day safeguard** (chosen): matches the agreed naming, keeps user-facing labels clean, and preserves updater ordering across channel switches.
+- **Calendar semver without a safeguard**: simplest display model, but alpha can become semver-older than Stable after a same-day promotion.
+- **Keep ADR-0057's next-patch prerelease numbering**: semver-safe, but it does not match the agreed release naming or the product surfaces that should show calendar-based versions.
+
+## Consequences
+
+- Release workflows now compute both a technical version and a display version.
+- User-facing version surfaces strip technical prerelease noise into clean labels (`Alpha YYYY.M.D.N` or `YYYY.M.D`).
+- Stable promotions must use `stable-vYYYY.M.D` tags instead of patch-based semver tags.
+- Alpha sequence numbers are scoped to a calendar core date and remain compatible with the updater manifests.
diff --git a/src-tauri/src/commands/mod.rs b/src-tauri/src/commands/mod.rs
index d9b9cb0e..c35ff28a 100644
--- a/src-tauri/src/commands/mod.rs
+++ b/src-tauri/src/commands/mod.rs
@@ -3,6 +3,7 @@ mod delete;
 mod git;
 mod system;
 mod vault;
+mod version;
 
 use std::borrow::Cow;
 
@@ -11,6 +12,7 @@ pub use delete::*;
 pub use git::*;
 pub use system::*;
 pub use vault::*;
+pub use version::*;
 
 /// Expand a leading `~` or `~/` in a path string to the user's home directory.
 /// Returns the original string unchanged if it doesn't start with `~` or if the
@@ -29,17 +31,6 @@ pub fn expand_tilde(path: &str) -> Cow<'_, str> {
     }
 }
 
-pub fn parse_build_label(version: &str) -> String {
-    let version = version.trim();
-    if version.is_empty() {
-        return "b?".to_string();
-    }
-
-    parse_legacy_build_label(version)
-        .or_else(|| parse_semver_build_label(version))
-        .unwrap_or_else(|| "b?".to_string())
-}
-
 fn is_numeric_version_part(part: &str) -> bool {
     !part.is_empty() && part.chars().all(|ch| ch.is_ascii_digit())
 }
@@ -56,30 +47,6 @@ fn parse_legacy_build_label(version: &str) -> Option<String> {
     }
 }
 
-fn parse_semver_build_label(version: &str) -> Option<String> {
-    let semver = version.split_once('+').map_or(version, |(base, _)| base);
-    let (core, prerelease) = semver
-        .split_once('-')
-        .map_or((semver, None), |(base, suffix)| (base, Some(suffix)));
-    let parts: Vec<&str> = core.split('.').collect();
-    let [major, minor, patch] = parts.as_slice() else {
-        return None;
-    };
-    if ![major, minor, patch]
-        .iter()
-        .all(|part| is_numeric_version_part(part))
-    {
-        return None;
-    }
-
-    match prerelease {
-        Some(suffix) if suffix.starts_with("alpha.") => Some(format!("alpha {}", version)),
-        Some(_) => Some(format!("v{}", version)),
-        None if version == "0.1.0" || version == "0.0.0" => Some("dev".to_string()),
-        None => Some(format!("v{}", version)),
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -115,35 +82,4 @@ mod tests {
         let result = expand_tilde("/home/~user/path");
         assert_eq!(result, "/home/~user/path");
     }
-
-    #[test]
-    fn parse_build_label_release_version() {
-        assert_eq!(parse_build_label("0.20260303.281"), "b281");
-        assert_eq!(parse_build_label("0.20251215.42"), "b42");
-    }
-
-    #[test]
-    fn parse_build_label_semver_releases() {
-        assert_eq!(parse_build_label("1.2.3"), "v1.2.3");
-        assert_eq!(
-            parse_build_label("1.2.4-alpha.202604122135.7"),
-            "alpha 1.2.4-alpha.202604122135.7"
-        );
-        assert_eq!(
-            parse_build_label("1.2.4-alpha.202604122135.7+darwin"),
-            "alpha 1.2.4-alpha.202604122135.7+darwin"
-        );
-    }
-
-    #[test]
-    fn parse_build_label_dev_version() {
-        assert_eq!(parse_build_label("0.1.0"), "dev");
-        assert_eq!(parse_build_label("0.0.0"), "dev");
-    }
-
-    #[test]
-    fn parse_build_label_malformed() {
-        assert_eq!(parse_build_label("invalid"), "b?");
-        assert_eq!(parse_build_label(""), "b?");
-    }
 }
diff --git a/src-tauri/src/commands/version.rs b/src-tauri/src/commands/version.rs
new file mode 100644
index 00000000..ba6b4967
--- /dev/null
+++ b/src-tauri/src/commands/version.rs
@@ -0,0 +1,121 @@
+use super::{is_numeric_version_part, parse_legacy_build_label};
+
+pub fn parse_build_label(version: &str) -> String {
+    let version = version.trim();
+    if version.is_empty() {
+        return "b?".to_string();
+    }
+
+    parse_legacy_build_label(version)
+        .or_else(|| parse_calendar_build_label(version))
+        .or_else(|| parse_semver_build_label(version))
+        .unwrap_or_else(|| "b?".to_string())
+}
+
+fn strip_build_metadata(version: &str) -> &str {
+    version.split_once('+').map_or(version, |(base, _)| base)
+}
+
+fn parse_calendar_build_label(version: &str) -> Option<String> {
+    let semver = strip_build_metadata(version);
+    let (core, prerelease) = semver
+        .split_once('-')
+        .map_or((semver, None), |(base, suffix)| (base, Some(suffix)));
+    let [year, month, day] = split_numeric_version_parts(core)?;
+    if year.len() != 4 {
+        return None;
+    }
+
+    let core_version = format!(
+        "{}.{}.{}",
+        year.parse::<u32>().ok()?,
+        month.parse::<u32>().ok()?,
+        day.parse::<u32>().ok()?
+    );
+
+    match prerelease {
+        Some(suffix) if suffix.starts_with("alpha.") => suffix
+            .strip_prefix("alpha.")
+            .map(|sequence| format!("Alpha {}.{}", core_version, sequence)),
+        Some(suffix) if suffix.starts_with("stable.") => Some(core_version),
+        Some(_) => None,
+        None => Some(core_version),
+    }
+}
+
+fn parse_semver_build_label(version: &str) -> Option<String> {
+    let semver = strip_build_metadata(version);
+    let (core, prerelease) = semver
+        .split_once('-')
+        .map_or((semver, None), |(base, suffix)| (base, Some(suffix)));
+    split_numeric_version_parts(core)?;
+
+    match prerelease {
+        Some(suffix) if suffix.starts_with("alpha.") => Some(format!("Alpha {}", semver)),
+        Some(_) => Some(format!("v{}", semver)),
+        None if semver == "0.1.0" || semver == "0.0.0" => Some("dev".to_string()),
+        None => Some(format!("v{}", semver)),
+    }
+}
+
+fn split_numeric_version_parts(version: &str) -> Option<[&str; 3]> {
+    let parts: Vec<&str> = version.split('.').collect();
+    let [major, minor, patch] = parts.as_slice() else {
+        return None;
+    };
+    if ![major, minor, patch]
+        .iter()
+        .all(|part| is_numeric_version_part(part))
+    {
+        return None;
+    }
+
+    Some([major, minor, patch])
+}
+
+#[cfg(test)]
+mod tests {
+    use super::parse_build_label;
+
+    #[test]
+    fn parse_build_label_release_version() {
+        assert_eq!(parse_build_label("0.20260303.281"), "b281");
+        assert_eq!(parse_build_label("0.20251215.42"), "b42");
+    }
+
+    #[test]
+    fn parse_build_label_calendar_versions() {
+        assert_eq!(parse_build_label("2026.4.16"), "2026.4.16");
+        assert_eq!(parse_build_label("2026.4.16-stable.1"), "2026.4.16");
+        assert_eq!(parse_build_label("2026.4.16-alpha.3"), "Alpha 2026.4.16.3");
+        assert_eq!(
+            parse_build_label("2026.4.16-alpha.3+darwin"),
+            "Alpha 2026.4.16.3"
+        );
+    }
+
+    #[test]
+    fn parse_build_label_legacy_semver_releases() {
+        assert_eq!(parse_build_label("1.2.3"), "v1.2.3");
+        assert_eq!(
+            parse_build_label("1.2.4-alpha.202604122135.7"),
+            "Alpha 1.2.4-alpha.202604122135.7"
+        );
+        assert_eq!(
+            parse_build_label("1.2.4-alpha.202604122135.7+darwin"),
+            "Alpha 1.2.4-alpha.202604122135.7"
+        );
+    }
+
+    #[test]
+    fn parse_build_label_dev_version() {
+        assert_eq!(parse_build_label("0.1.0"), "dev");
+        assert_eq!(parse_build_label("0.0.0"), "dev");
+    }
+
+    #[test]
+    fn parse_build_label_malformed() {
+        assert_eq!(parse_build_label("invalid"), "b?");
+        assert_eq!(parse_build_label(""), "b?");
+    }
+}
diff --git a/src/components/UpdateBanner.test.tsx b/src/components/UpdateBanner.test.tsx
index 46750c91..efe2f67f 100644
--- a/src/components/UpdateBanner.test.tsx
+++ b/src/components/UpdateBanner.test.tsx
@@ -21,64 +21,93 @@ function makeActions(overrides?: Partial<UpdateActions>): UpdateActions {
   }
 }
 
+function makeAvailableStatus(overrides?: Partial<Extract<UpdateStatus, { state: 'available' }>>): UpdateStatus {
+  return {
+    state: 'available',
+    version: '2026.4.16',
+    displayVersion: '2026.4.16',
+    notes: undefined,
+    ...overrides,
+  }
+}
+
+function makeDownloadingStatus(overrides?: Partial<Extract<UpdateStatus, { state: 'downloading' }>>): UpdateStatus {
+  return {
+    state: 'downloading',
+    version: '2026.4.16-alpha.3',
+    displayVersion: 'Alpha 2026.4.16.3',
+    progress: 0.65,
+    ...overrides,
+  }
+}
+
+function makeReadyStatus(overrides?: Partial<Extract<UpdateStatus, { state: 'ready' }>>): UpdateStatus {
+  return {
+    state: 'ready',
+    version: '2026.4.16',
+    displayVersion: '2026.4.16',
+    ...overrides,
+  }
+}
+
+function renderBanner(status: UpdateStatus, actions = makeActions()) {
+  const view = render(<UpdateBanner status={status} actions={actions} />)
+  return { ...view, actions }
+}
+
 describe('UpdateBanner', () => {
   it('renders nothing when idle', () => {
     const status: UpdateStatus = { state: 'idle' }
-    const { container } = render(<UpdateBanner status={status} actions={makeActions()} />)
+    const { container } = renderBanner(status)
     expect(container.innerHTML).toBe('')
   })
 
   it('renders nothing on error state', () => {
     const status: UpdateStatus = { state: 'error' }
-    const { container } = render(<UpdateBanner status={status} actions={makeActions()} />)
+    const { container } = renderBanner(status)
     expect(container.innerHTML).toBe('')
   })
 
   it('shows version and action buttons when update is available', () => {
-    const status: UpdateStatus = { state: 'available', version: '1.5.0', notes: 'Bug fixes' }
-    const actions = makeActions()
-    render(<UpdateBanner status={status} actions={actions} />)
+    renderBanner(makeAvailableStatus({
+      version: '2026.4.16-alpha.3',
+      displayVersion: 'Alpha 2026.4.16.3',
+      notes: 'Bug fixes',
+    }))
 
     expect(screen.getByTestId('update-banner')).toBeTruthy()
-    expect(screen.getByText(/Tolaria 1\.5\.0/)).toBeTruthy()
-    expect(screen.getByText('is available')).toBeTruthy()
+    expect(screen.getByText(/Tolaria Alpha 2026\.4\.16\.3/)).toBeTruthy()
+    expect(screen.getByText(/is available/)).toBeTruthy()
     expect(screen.getByTestId('update-now-btn')).toBeTruthy()
     expect(screen.getByTestId('update-release-notes')).toBeTruthy()
     expect(screen.getByTestId('update-dismiss')).toBeTruthy()
   })
 
   it('"Update Now" calls startDownload', () => {
-    const status: UpdateStatus = { state: 'available', version: '1.5.0', notes: undefined }
-    const actions = makeActions()
-    render(<UpdateBanner status={status} actions={actions} />)
+    const { actions } = renderBanner(makeAvailableStatus())
 
     fireEvent.click(screen.getByTestId('update-now-btn'))
     expect(actions.startDownload).toHaveBeenCalledOnce()
   })
 
   it('"Release Notes" link calls openReleaseNotes', () => {
-    const status: UpdateStatus = { state: 'available', version: '1.5.0', notes: undefined }
-    const actions = makeActions()
-    render(<UpdateBanner status={status} actions={actions} />)
+    const { actions } = renderBanner(makeAvailableStatus())
 
     fireEvent.click(screen.getByTestId('update-release-notes'))
     expect(actions.openReleaseNotes).toHaveBeenCalledOnce()
   })
 
   it('dismiss button calls dismiss action', () => {
-    const status: UpdateStatus = { state: 'available', version: '1.5.0', notes: undefined }
-    const actions = makeActions()
-    render(<UpdateBanner status={status} actions={actions} />)
+    const { actions } = renderBanner(makeAvailableStatus())
 
     fireEvent.click(screen.getByTestId('update-dismiss'))
     expect(actions.dismiss).toHaveBeenCalledOnce()
   })
 
   it('shows progress bar during download', () => {
-    const status: UpdateStatus = { state: 'downloading', version: '1.5.0', progress: 0.65 }
-    render(<UpdateBanner status={status} actions={makeActions()} />)
+    renderBanner(makeDownloadingStatus())
 
-    expect(screen.getByText(/Downloading Tolaria 1\.5\.0/)).toBeTruthy()
+    expect(screen.getByText(/Downloading Tolaria Alpha 2026\.4\.16\.3/)).toBeTruthy()
     expect(screen.getByText('65%')).toBeTruthy()
 
     const progressBar = screen.getByTestId('update-progress')
@@ -86,8 +115,11 @@ describe('UpdateBanner', () => {
   })
 
   it('shows 0% at start of download', () => {
-    const status: UpdateStatus = { state: 'downloading', version: '2.0.0', progress: 0 }
-    render(<UpdateBanner status={status} actions={makeActions()} />)
+    renderBanner(makeDownloadingStatus({
+      version: '2026.4.16',
+      displayVersion: '2026.4.16',
+      progress: 0,
+    }))
 
     expect(screen.getByText('0%')).toBeTruthy()
     const progressBar = screen.getByTestId('update-progress')
@@ -95,18 +127,16 @@ describe('UpdateBanner', () => {
   })
 
   it('shows restart button when update is ready', () => {
-    const status: UpdateStatus = { state: 'ready', version: '1.5.0' }
-    render(<UpdateBanner status={status} actions={makeActions()} />)
+    renderBanner(makeReadyStatus())
 
-    expect(screen.getByText(/Tolaria 1\.5\.0/)).toBeTruthy()
+    expect(screen.getByText(/Tolaria 2026\.4\.16/)).toBeTruthy()
     expect(screen.getByText(/restart to apply/)).toBeTruthy()
     expect(screen.getByTestId('update-restart-btn')).toBeTruthy()
   })
 
   it('restart button calls restartApp', async () => {
     const { restartApp } = await import('../hooks/useUpdater')
-    const status: UpdateStatus = { state: 'ready', version: '1.5.0' }
-    render(<UpdateBanner status={status} actions={makeActions()} />)
+    renderBanner(makeReadyStatus())
 
     fireEvent.click(screen.getByTestId('update-restart-btn'))
     expect(restartApp).toHaveBeenCalled()
diff --git a/src/components/UpdateBanner.tsx b/src/components/UpdateBanner.tsx
index 541b0e80..36d4e71d 100644
--- a/src/components/UpdateBanner.tsx
+++ b/src/components/UpdateBanner.tsx
@@ -1,145 +1,166 @@
+import type { CSSProperties } from 'react'
 import { Download, ExternalLink, RefreshCw, X } from 'lucide-react'
 import type { UpdateStatus, UpdateActions } from '../hooks/useUpdater'
 import { restartApp } from '../hooks/useUpdater'
+import { Button } from './ui/button'
 
 interface UpdateBannerProps {
   status: UpdateStatus
   actions: UpdateActions
 }
 
+type VisibleUpdateStatus = Exclude<UpdateStatus, { state: 'idle' } | { state: 'error' }>
+
+const bannerStyle = {
+  display: 'flex',
+  alignItems: 'center',
+  gap: 10,
+  padding: '6px 12px',
+  background: '#1a56db',
+  borderBottom: 'none',
+  fontSize: 13,
+  color: '#fff',
+  flexShrink: 0,
+} satisfies CSSProperties
+
+const iconStyle = {
+  color: '#fff',
+  flexShrink: 0,
+} satisfies CSSProperties
+
+const primaryActionStyle = {
+  marginLeft: 'auto',
+  padding: '3px 10px',
+  background: 'var(--primary)',
+  color: '#fff',
+  fontSize: 12,
+  fontWeight: 500,
+} satisfies CSSProperties
+
+const dismissButtonStyle = {
+  color: '#fff',
+  display: 'flex',
+  padding: 2,
+} satisfies CSSProperties
+
+const progressTrackStyle = {
+  flex: 1,
+  maxWidth: 200,
+  height: 4,
+  background: 'rgba(255,255,255,0.3)',
+  borderRadius: 2,
+  overflow: 'hidden',
+} satisfies CSSProperties
+
+const progressTextStyle = {
+  fontSize: 11,
+  color: 'rgba(255,255,255,0.85)',
+} satisfies CSSProperties
+
+const readyIconStyle = {
+  color: 'var(--accent-green, #0F7B0F)',
+  flexShrink: 0,
+} satisfies CSSProperties
+
+function renderAvailableContent(status: Extract<VisibleUpdateStatus, { state: 'available' }>, actions: UpdateActions) {
+  return (
+    <>
+      <Download size={14} style={iconStyle} />
+      <span>
+        <strong>Tolaria {status.displayVersion}</strong> is available
+      </span>
+      <Button
+        type="button"
+        variant="link"
+        size="xs"
+        data-testid="update-release-notes"
+        onClick={actions.openReleaseNotes}
+        style={{ color: '#fff', padding: 0, height: 'auto' }}
+      >
+        Release Notes <ExternalLink size={11} />
+      </Button>
+      <Button
+        type="button"
+        size="xs"
+        data-testid="update-now-btn"
+        onClick={actions.startDownload}
+        style={primaryActionStyle}
+      >
+        Update Now
+      </Button>
+      <Button
+        type="button"
+        variant="ghost"
+        size="icon-xs"
+        data-testid="update-dismiss"
+        onClick={actions.dismiss}
+        style={dismissButtonStyle}
+        aria-label="Dismiss"
+      >
+        <X size={14} />
+      </Button>
+    </>
+  )
+}
+
+function renderDownloadingContent(status: Extract<VisibleUpdateStatus, { state: 'downloading' }>) {
+  return (
+    <>
+      <RefreshCw size={14} style={{ ...iconStyle, animation: 'spin 1s linear infinite' }} />
+      <span>Downloading Tolaria {status.displayVersion}...</span>
+      <div style={progressTrackStyle}>
+        <div
+          data-testid="update-progress"
+          style={{
+            width: `${Math.round(status.progress * 100)}%`,
+            height: '100%',
+            background: 'var(--primary)',
+            borderRadius: 2,
+            transition: 'width 0.2s ease',
+          }}
+        />
+      </div>
+      <span style={progressTextStyle}>{Math.round(status.progress * 100)}%</span>
+    </>
+  )
+}
+
+function renderReadyContent(status: Extract<VisibleUpdateStatus, { state: 'ready' }>) {
+  return (
+    <>
+      <RefreshCw size={14} style={readyIconStyle} />
+      <span>
+        <strong>Tolaria {status.displayVersion}</strong> is ready - restart to apply
+      </span>
+      <Button
+        type="button"
+        size="xs"
+        data-testid="update-restart-btn"
+        onClick={restartApp}
+        style={{
+          ...primaryActionStyle,
+          background: 'var(--accent-green, #0F7B0F)',
+        }}
+      >
+        Restart Now
+      </Button>
+    </>
+  )
+}
+
+function renderBannerContent(status: VisibleUpdateStatus, actions: UpdateActions) {
+  switch (status.state) {
+    case 'available':
+      return renderAvailableContent(status, actions)
+    case 'downloading':
+      return renderDownloadingContent(status)
+    case 'ready':
+      return renderReadyContent(status)
+  }
+}
+
 export function UpdateBanner({ status, actions }: UpdateBannerProps) {
   if (status.state === 'idle' || status.state === 'error') return null
 
-  return (
-    <div
-      data-testid="update-banner"
-      style={{
-        display: 'flex',
-        alignItems: 'center',
-        gap: 10,
-        padding: '6px 12px',
-        background: '#1a56db',
-        borderBottom: 'none',
-        fontSize: 13,
-        color: '#fff',
-        flexShrink: 0,
-      }}
-    >
-      {status.state === 'available' && (
-        <>
-          <Download size={14} style={{ color: '#fff', flexShrink: 0 }} />
-          <span>
-            <strong>Tolaria {status.version}</strong> is available
-          </span>
-          <button
-            data-testid="update-release-notes"
-            onClick={actions.openReleaseNotes}
-            style={{
-              display: 'inline-flex',
-              alignItems: 'center',
-              gap: 3,
-              background: 'none',
-              border: 'none',
-              color: '#fff',
-              cursor: 'pointer',
-              fontSize: 13,
-              padding: 0,
-              textDecoration: 'underline',
-            }}
-          >
-            Release Notes <ExternalLink size={11} />
-          </button>
-          <button
-            data-testid="update-now-btn"
-            onClick={actions.startDownload}
-            style={{
-              marginLeft: 'auto',
-              padding: '3px 10px',
-              background: 'var(--primary)',
-              color: '#fff',
-              border: 'none',
-              borderRadius: 5,
-              fontSize: 12,
-              fontWeight: 500,
-              cursor: 'pointer',
-            }}
-          >
-            Update Now
-          </button>
-          <button
-            data-testid="update-dismiss"
-            onClick={actions.dismiss}
-            style={{
-              background: 'none',
-              border: 'none',
-              cursor: 'pointer',
-              color: '#fff',
-              display: 'flex',
-              padding: 2,
-            }}
-            aria-label="Dismiss"
-          >
-            <X size={14} />
-          </button>
-        </>
-      )}
-
-      {status.state === 'downloading' && (
-        <>
-          <RefreshCw size={14} style={{ color: '#fff', flexShrink: 0, animation: 'spin 1s linear infinite' }} />
-          <span>Downloading Tolaria {status.version}...</span>
-          <div
-            style={{
-              flex: 1,
-              maxWidth: 200,
-              height: 4,
-              background: 'rgba(255,255,255,0.3)',
-              borderRadius: 2,
-              overflow: 'hidden',
-            }}
-          >
-            <div
-              data-testid="update-progress"
-              style={{
-                width: `${Math.round(status.progress * 100)}%`,
-                height: '100%',
-                background: 'var(--primary)',
-                borderRadius: 2,
-                transition: 'width 0.2s ease',
-              }}
-            />
-          </div>
-          <span style={{ fontSize: 11, color: 'var(--muted-foreground)' }}>
-            {Math.round(status.progress * 100)}%
-          </span>
-        </>
-      )}
-
-      {status.state === 'ready' && (
-        <>
-          <RefreshCw size={14} style={{ color: 'var(--accent-green, #0F7B0F)', flexShrink: 0 }} />
-          <span>
-            <strong>Tolaria {status.version}</strong> is ready — restart to apply
-          </span>
-          <button
-            data-testid="update-restart-btn"
-            onClick={restartApp}
-            style={{
-              marginLeft: 'auto',
-              padding: '3px 10px',
-              background: 'var(--accent-green, #0F7B0F)',
-              color: '#fff',
-              border: 'none',
-              borderRadius: 5,
-              fontSize: 12,
-              fontWeight: 500,
-              cursor: 'pointer',
-            }}
-          >
-            Restart Now
-          </button>
-        </>
-      )}
-    </div>
-  )
+  return <div data-testid="update-banner" style={bannerStyle}>{renderBannerContent(status, actions)}</div>
 }
diff --git a/src/hooks/useUpdater.test.ts b/src/hooks/useUpdater.test.ts
index 22929ad3..7316c5fd 100644
--- a/src/hooks/useUpdater.test.ts
+++ b/src/hooks/useUpdater.test.ts
@@ -48,8 +48,8 @@ type DownloadArgs = {
 
 function makeUpdate(overrides: Partial<AppUpdateMetadata> = {}): AppUpdateMetadata {
   return {
-    currentVersion: '1.0.0',
-    version: '1.2.0',
+    currentVersion: '2026.4.15',
+    version: '2026.4.16',
     body: 'Bug fixes and improvements',
     ...overrides,
   }
@@ -148,12 +148,13 @@ describe('useUpdater', () => {
   it('transitions to available when an alpha update is found', async () => {
     const { result } = await performManualCheck(
       'alpha',
-      makeUpdate({ version: '1.2.4-alpha.202604121830.10' }),
+      makeUpdate({ version: '2026.4.16-alpha.3' }),
     )
 
     expect(result.current.status).toEqual({
       state: 'available',
-      version: '1.2.4-alpha.202604121830.10',
+      version: '2026.4.16-alpha.3',
+      displayVersion: 'Alpha 2026.4.16.3',
       notes: 'Bug fixes and improvements',
     })
 
@@ -178,11 +179,26 @@ describe('useUpdater', () => {
     expect(outcome).toBe('available')
     expect(result.current.status).toEqual({
       state: 'available',
-      version: '1.2.0',
+      version: '2026.4.16',
+      displayVersion: '2026.4.16',
       notes: undefined,
     })
   })
 
+  it('strips stable prerelease suffixes from the display version', async () => {
+    const { result } = await performManualCheck(
+      'stable',
+      makeUpdate({ version: '2026.4.16-stable.1' }),
+    )
+
+    expect(result.current.status).toEqual({
+      state: 'available',
+      version: '2026.4.16-stable.1',
+      displayVersion: '2026.4.16',
+      notes: 'Bug fixes and improvements',
+    })
+  })
+
   it('returns error when the update check fails', async () => {
     const { result, outcome } = await performManualCheck(
       'stable',
@@ -231,7 +247,7 @@ describe('useUpdater', () => {
       checkResult: makeUpdate(),
       downloadImpl: async (args) => {
         expect(args.releaseChannel).toBe('stable')
-        expect(args.expectedVersion).toBe('1.2.0')
+        expect(args.expectedVersion).toBe('2026.4.16')
         args.onEvent.onmessage({ event: 'Started', data: { contentLength: 1000 } })
         args.onEvent.onmessage({ event: 'Progress', data: { chunkLength: 500 } })
         args.onEvent.onmessage({ event: 'Progress', data: { chunkLength: 500 } })
@@ -249,7 +265,11 @@ describe('useUpdater', () => {
       await result.current.actions.startDownload()
     })
 
-    expect(result.current.status).toEqual({ state: 'ready', version: '1.2.0' })
+    expect(result.current.status).toEqual({
+      state: 'ready',
+      version: '2026.4.16',
+      displayVersion: '2026.4.16',
+    })
   })
 
   it('transitions to error when download fails', async () => {
diff --git a/src/hooks/useUpdater.ts b/src/hooks/useUpdater.ts
index 2706b414..ec560471 100644
--- a/src/hooks/useUpdater.ts
+++ b/src/hooks/useUpdater.ts
@@ -9,12 +9,18 @@ import {
 import { openExternalUrl } from '../utils/url'
 
 const RELEASE_NOTES_URL = 'https://refactoringhq.github.io/tolaria/'
+const CALENDAR_VERSION_PATTERN = /^(\d{4})\.(\d{1,2})\.(\d{1,2})(?:-(alpha|stable)\.(\d+))?$/
+
+interface UpdateVersionInfo {
+  version: string
+  displayVersion: string
+}
 
 export type UpdateStatus =
   | { state: 'idle' }
-  | { state: 'available'; version: string; notes: string | undefined }
-  | { state: 'downloading'; version: string; progress: number }
-  | { state: 'ready'; version: string }
+  | ({ state: 'available'; notes: string | undefined } & UpdateVersionInfo)
+  | ({ state: 'downloading'; progress: number } & UpdateVersionInfo)
+  | ({ state: 'ready' } & UpdateVersionInfo)
   | { state: 'error' }
 
 export type UpdateCheckResult = 'up-to-date' | 'available' | 'error'
@@ -26,16 +32,41 @@ export interface UpdateActions {
   dismiss: () => void
 }
 
+function formatReleaseDisplayVersion(version: string): string {
+  const normalizedVersion = version.trim()
+  if (!normalizedVersion) return normalizedVersion
+
+  const baseVersion = normalizedVersion.split('+')[0]
+  const match = baseVersion.match(CALENDAR_VERSION_PATTERN)
+  if (!match) return baseVersion
+
+  const [, year, month, day, channel, sequence] = match
+  const calendarVersion = `${Number(year)}.${Number(month)}.${Number(day)}`
+
+  if (channel === 'alpha' && sequence) {
+    return `Alpha ${calendarVersion}.${Number(sequence)}`
+  }
+
+  return calendarVersion
+}
+
+function createVersionInfo(version: string): UpdateVersionInfo {
+  return {
+    version,
+    displayVersion: formatReleaseDisplayVersion(version),
+  }
+}
+
 function toAvailableStatus(update: AppUpdateMetadata): UpdateStatus {
   return {
     state: 'available',
-    version: update.version,
+    ...createVersionInfo(update.version),
     notes: update.body ?? undefined,
   }
 }
 
 function createDownloadProgressHandler(
-  version: string,
+  versionInfo: UpdateVersionInfo,
   setStatus: Dispatch<SetStateAction<UpdateStatus>>,
 ): (event: AppUpdateDownloadEvent) => void {
   let totalBytes = 0
@@ -50,11 +81,11 @@ function createDownloadProgressHandler(
     if (event.event === 'Progress') {
       downloadedBytes += event.data.chunkLength
       const progress = totalBytes > 0 ? Math.min(downloadedBytes / totalBytes, 1) : 0
-      setStatus({ state: 'downloading', version, progress })
+      setStatus({ state: 'downloading', ...versionInfo, progress })
       return
     }
 
-    setStatus({ state: 'ready', version })
+    setStatus({ state: 'ready', ...versionInfo })
   }
 }
 
@@ -94,17 +125,18 @@ export function useUpdater(
     const update = updateRef.current
     if (!update) return
 
-    setStatus({ state: 'downloading', version: update.version, progress: 0 })
+    const versionInfo = createVersionInfo(update.version)
+    setStatus({ state: 'downloading', ...versionInfo, progress: 0 })
 
     try {
       await downloadAndInstallAppUpdate(
         releaseChannel,
         update.version,
-        createDownloadProgressHandler(update.version, setStatus),
+        createDownloadProgressHandler(versionInfo, setStatus),
       )
 
       // If Finished wasn't emitted via callback, set ready after await resolves
-      setStatus((prev) => (prev.state === 'downloading' ? { state: 'ready', version: update.version } : prev))
+      setStatus((prev) => (prev.state === 'downloading' ? { state: 'ready', ...versionInfo } : prev))
     } catch {
       console.warn('[updater] Download failed')
       setStatus({ state: 'error' })
