diff --git a/CHANGELOG.md b/CHANGELOG.md
index e4373ed1..77ce99cd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,24 @@
 # Changelog
 
+## 1.5.3 (2026-04-28)
+
+> **New:** Bulwark Webmail now sends an anonymous instance heartbeat once per day (version, platform, bucketed account counts, feature toggles — no message data, no PII). Disable any time from **Admin → Telemetry** or by setting `BULWARK_TELEMETRY=off`. See the [privacy notice](https://bulwarkmail.org/docs/legal/privacy/telemetry) for the full schema.
+
+### Features
+
+- **Telemetry**: Anonymous instance telemetry, on by default. Reports schema version, platform, bucketed account counts, and feature toggles only — disable from the admin UI, with `BULWARK_TELEMETRY=off`, or by clearing the endpoint
+- **Telemetry**: Track unique logins (HMAC'd per instance, 90-day retention) so the heartbeat can report bucketed account totals without storing usernames
+- **Plugins**: Theme API v2 with token compiler and skin slot
+- **Plugins**: Extension preview page and detailed extension info API
+- **Calendar**: Right-click context menu on empty calendar space
+- **Docker**: Persistent named volume for telemetry data so the instance id and admin's consent choice survive container upgrades
+
+### Fixes
+
+- **Security**: Block telemetry endpoint from pointing at internal/loopback hosts (validation + DNS-rebind re-check at fetch time)
+- **Security**: Harden plugin config, TOTP token exchange, and branding file serving
+- **Mail**: Batch shortcuts now act on the multi-selection when one is present (#228)
+
 ## 1.5.2 (2026-04-27)
 
 ### Features
diff --git a/README.md b/README.md
index 05c7f005..1d46afb6 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@ A modern, self-hosted webmail client for [Stalwart Mail Server](https://stalw.ar
 
 [![License: AGPL v3](https://img.shields.io/badge/license-AGPL%20v3-blue.svg?logo=gnu&logoColor=white)](LICENSE)
 [![Discord](https://img.shields.io/discord/1482128142939455674?color=7289da&label=discord&logo=discord&logoColor=white)](https://discord.gg/tYCujymGrT)
-[![Version](https://img.shields.io/badge/version-1.5.2-green.svg?logo=git&logoColor=white)](CHANGELOG.md)
+[![Version](https://img.shields.io/badge/version-1.5.3-green.svg?logo=git&logoColor=white)](CHANGELOG.md)
 [![Docker](https://img.shields.io/badge/docker-ghcr.io%2Fbulwarkmail%2Fwebmail-blue?logo=docker&logoColor=white)](https://ghcr.io/bulwarkmail/webmail)
 
 </div>
@@ -53,6 +53,8 @@ A modern, self-hosted webmail client for [Stalwart Mail Server](https://stalw.ar
 </tr>
 </table>
 
+> **Anonymous telemetry is on by default** since 1.5.3. Each instance sends a daily heartbeat (version, platform, bucketed account counts, feature toggles — no message data, no PII). Disable from **Admin → Telemetry**, by setting `BULWARK_TELEMETRY=off`, or by clearing the endpoint. Full schema: [privacy notice](https://bulwarkmail.org/docs/legal/privacy/telemetry).
+
 ## Overview
 
 Bulwark is a full webmail suite – not just an inbox. It bundles the four apps most self-hosters end up wanting on the same login:
diff --git a/VERSION b/VERSION
index 4cda8f19..8af85beb 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.5.2
+1.5.3
diff --git a/app/admin/telemetry/page.tsx b/app/admin/telemetry/page.tsx
index 29ddd72c..ea60ab33 100644
--- a/app/admin/telemetry/page.tsx
+++ b/app/admin/telemetry/page.tsx
@@ -137,7 +137,7 @@ export default function AdminTelemetryPage() {
           <div>
             <div className="font-medium">Status</div>
             <div className="text-sm text-muted-foreground">
-              {status.consent === 'pending' && 'Initialising — no heartbeats sent yet.'}
+              {status.consent === 'pending' && 'Initialising - no heartbeats sent yet.'}
               {status.consent === 'on' && 'Heartbeats are enabled (default).'}
               {status.consent === 'off' && 'Heartbeats are off.'}
               {envOverridden && (
diff --git a/app/api/auth/totp-token-exchange/route.ts b/app/api/auth/totp-token-exchange/route.ts
index f311faec..9b1dca47 100644
--- a/app/api/auth/totp-token-exchange/route.ts
+++ b/app/api/auth/totp-token-exchange/route.ts
@@ -89,7 +89,7 @@ export async function POST(request: NextRequest) {
     // Pin the upstream URL to the configured JMAP server so an unauthenticated
     // caller cannot point this route at internal hosts. Only when no server
     // URL is configured (and the deployment explicitly allows custom JMAP
-    // endpoints) do we fall back to the user-supplied URL — and even then
+    // endpoints) do we fall back to the user-supplied URL - and even then
     // it must resolve to a public address.
     await configManager.ensureLoaded();
     const configuredServerUrl =
diff --git a/lib/plugin-storage.ts b/lib/plugin-storage.ts
index eefcf4f1..51ef42b8 100644
--- a/lib/plugin-storage.ts
+++ b/lib/plugin-storage.ts
@@ -88,7 +88,7 @@ export const pluginStorage = {
     await deleteItem(STORE_THEMES, themeId);
   },
 
-  // Theme skin CSS — separate store so it can be present/absent independently
+  // Theme skin CSS - separate store so it can be present/absent independently
   // of the colour-token CSS (e.g. some v2 themes ship colours only).
   async saveThemeSkin(themeId: string, skin: string): Promise<void> {
     await putItem(STORE_THEME_SKINS, themeId, skin);
diff --git a/lib/plugin-types.ts b/lib/plugin-types.ts
index 1cf90275..b85f6cb7 100644
--- a/lib/plugin-types.ts
+++ b/lib/plugin-types.ts
@@ -12,7 +12,7 @@ export type ThemeVariant = 'light' | 'dark';
 // ─── Manifests ───────────────────────────────────────────────
 
 /**
- * Advanced theme fields ("Theme API v2"). All optional and additive — a
+ * Advanced theme fields ("Theme API v2"). All optional and additive - a
  * legacy theme that ships only `:root`/`.dark` CSS continues to work.
  *
  * When `apiVersion >= 2` (or any of `tokens`/`extends`/`derive`/`density`/
@@ -62,7 +62,7 @@ export interface ThemeManifest {
   apiVersion?: 1 | 2;
   /** Inherit tokens/CSS from another installed (or built-in) theme by id. */
   extends?: string;
-  /** Structured colour tokens — compiled into CSS at install time. */
+  /** Structured colour tokens - compiled into CSS at install time. */
   tokens?: ThemeTokenSet;
   /** When true, missing standard tokens are derived (e.g. *-foreground from contrast). */
   derive?: boolean;
@@ -121,10 +121,10 @@ export interface InstalledTheme {
   author: string;
   description: string;
   preview?: string;       // data: URI or blob URL
-  css: string;            // compiled CSS text — what gets injected
+  css: string;            // compiled CSS text - what gets injected
   /**
    * Optional "skin" CSS shipped by Theme API v2 themes that need to restyle
-   * actual UI components (toolbars, lists, buttons, etc.) — not just colour
+   * actual UI components (toolbars, lists, buttons, etc.) - not just colour
    * tokens. Injected into a separate `<style>` tag so it can be stripped
    * cleanly when the theme is deactivated. Stored in IndexedDB with the same
    * lifecycle as `css` to keep localStorage small.
@@ -598,7 +598,7 @@ export const MAX_PLUGIN_SIZE = 5 * 1024 * 1024; // 5 MB
 export const MAX_THEME_SIZE = 2 * 1024 * 1024;  // 2 MB (was 1 MB; v2 themes may ship a skin.css)
 /**
  * Maximum size of an individual `skin.css` payload after extraction.
- * Skins are component-level CSS, not images — anything bigger than this is
+ * Skins are component-level CSS, not images - anything bigger than this is
  * almost certainly bundling assets the validator will refuse anyway.
  */
 export const MAX_THEME_SKIN_BYTES = 256 * 1024; // 256 KB
diff --git a/lib/plugin-validator.ts b/lib/plugin-validator.ts
index cec2e24f..d7aa0168 100644
--- a/lib/plugin-validator.ts
+++ b/lib/plugin-validator.ts
@@ -24,7 +24,7 @@ export interface ThemeExtractionResult extends ValidationResult {
   manifest: ThemeManifest | null;
   css: string;
   /**
-   * Optional skin CSS — component-level overrides extracted from `skin.css`.
+   * Optional skin CSS - component-level overrides extracted from `skin.css`.
    * Only populated for Theme API v2 manifests; v1 themes ignore the file.
    */
   skin: string | null;
@@ -225,7 +225,7 @@ export async function extractTheme(file: File): Promise<ThemeExtractionResult> {
     return { valid: false, errors, warnings, manifest: null, css: '', skin: null, preview: null };
   }
 
-  // Read theme.css — required for v1 themes, optional when the manifest
+  // Read theme.css - required for v1 themes, optional when the manifest
   // declares Theme API v2 fields (tokens/extends/derive/density/radii/typography),
   // since the compiler can produce CSS purely from the manifest.
   const cssFile = zip.file(root + 'theme.css');
@@ -279,13 +279,13 @@ export async function extractTheme(file: File): Promise<ThemeExtractionResult> {
   }
 
   // Read skin.css if present (Theme API v2 only). Skins target real
-  // component selectors and bypass the strict :root/.dark selector check —
+  // component selectors and bypass the strict :root/.dark selector check -
   // they still go through the dangerous-pattern sanitizer.
   let skin: string | null = null;
   const skinFile = zip.file(root + 'skin.css');
   if (skinFile) {
     if (!isAdvanced) {
-      warnings.push('skin.css ignored — only Theme API v2 manifests can ship a skin');
+      warnings.push('skin.css ignored - only Theme API v2 manifests can ship a skin');
     } else {
       const rawSkin = await skinFile.async('string');
       if (rawSkin.length > MAX_THEME_SKIN_BYTES) {
diff --git a/lib/telemetry/endpoint-guard.ts b/lib/telemetry/endpoint-guard.ts
index 529f160b..12432227 100644
--- a/lib/telemetry/endpoint-guard.ts
+++ b/lib/telemetry/endpoint-guard.ts
@@ -6,7 +6,7 @@ import { isIP } from 'node:net';
 // URL; without this an attacker with a session (or a hostile admin in a
 // multi-tenant deploy) could redirect heartbeats at internal hosts.
 //
-// Set BULWARK_TELEMETRY_ALLOW_PRIVATE=1 to bypass — useful only for local
+// Set BULWARK_TELEMETRY_ALLOW_PRIVATE=1 to bypass - useful only for local
 // dev where the collector is on the loopback.
 
 const PRIVATE_V4: RegExp[] = [
@@ -106,7 +106,7 @@ export async function resolveEndpointAllowed(raw: string): Promise<EndpointCheck
     }
     return { ok: true };
   } catch {
-    // Don't block on transient DNS failures — fetch will fail loudly anyway,
+    // Don't block on transient DNS failures - fetch will fail loudly anyway,
     // and we don't want to lock admins out of their config when the resolver
     // is flaky. The literal-IP check above already covers the direct-attack
     // case.
diff --git a/lib/telemetry/state.ts b/lib/telemetry/state.ts
index ff94802e..48b1ab27 100644
--- a/lib/telemetry/state.ts
+++ b/lib/telemetry/state.ts
@@ -41,7 +41,7 @@ export async function getInstanceId(): Promise<string> {
   return fresh;
 }
 
-// Default consent is 'on' — telemetry is anonymous and enabled by default.
+// Default consent is 'on' - telemetry is anonymous and enabled by default.
 // Admins can disable via the UI, the BULWARK_TELEMETRY env var, or by clearing
 // the endpoint. See https://bulwarkmail.org/docs/legal/privacy/telemetry.
 const DEFAULTS: TelemetryStateFile = {
diff --git a/lib/theme-compiler.ts b/lib/theme-compiler.ts
index b805368c..55f3c6b6 100644
--- a/lib/theme-compiler.ts
+++ b/lib/theme-compiler.ts
@@ -1,4 +1,4 @@
-// Advanced Theme API v2 — compiles structured manifest fields (tokens,
+// Advanced Theme API v2 - compiles structured manifest fields (tokens,
 // radii, typography, density, extends) into a single CSS string that the
 // existing `injectThemeCSS` pipeline can apply unchanged.
 
@@ -79,11 +79,11 @@ function emitTokens(
   for (const [rawKey, value] of Object.entries(expanded)) {
     if (typeof value !== 'string' || !value.trim()) continue;
     if (!isSafeTokenKey(rawKey)) {
-      warnings.push(`Token "${rawKey}" dropped — invalid key (only [a-z0-9-] allowed)`);
+      warnings.push(`Token "${rawKey}" dropped - invalid key (only [a-z0-9-] allowed)`);
       continue;
     }
     if (!isSafeTokenValue(value)) {
-      warnings.push(`Token "${rawKey}" dropped — value contains unsafe characters`);
+      warnings.push(`Token "${rawKey}" dropped - value contains unsafe characters`);
       continue;
     }
     lines.push(`  ${tokenName(rawKey)}: ${value.trim()};`);
@@ -170,7 +170,7 @@ export interface CompileOptions {
   /**
    * Resolves a `extends: <id>` chain to that base theme's compiled CSS.
    * Implementations should return null for unknown ids; circular refs are
-   * the caller's problem (we don't recurse — just one level of inheritance).
+   * the caller's problem (we don't recurse - just one level of inheritance).
    */
   resolveExtends?: (id: string) => string | null;
   /**
@@ -211,16 +211,16 @@ export function compileAdvancedTheme(
 
   const sections: string[] = [];
 
-  // 1. extends — prepend parent CSS verbatim
+  // 1. extends - prepend parent CSS verbatim
   if (manifest.extends && opts.resolveExtends) {
     const parentCSS = opts.resolveExtends(manifest.extends);
     if (parentCSS == null) {
-      warnings.push(`extends: parent theme "${manifest.extends}" not found — skipping`);
+      warnings.push(`extends: parent theme "${manifest.extends}" not found - skipping`);
     } else {
       sections.push(`/* inherited from ${manifest.extends} */\n${parentCSS}`);
     }
   } else if (manifest.extends) {
-    warnings.push(`extends: no resolver provided — "${manifest.extends}" ignored`);
+    warnings.push(`extends: no resolver provided - "${manifest.extends}" ignored`);
   }
 
   // 2. :root block (light + common + structural)
@@ -268,7 +268,7 @@ export function compileAdvancedTheme(
   }
 
   if (sections.length === 0) {
-    errors.push('Compiled theme is empty — no tokens, radii, typography, or density supplied');
+    errors.push('Compiled theme is empty - no tokens, radii, typography, or density supplied');
   }
 
   return {
diff --git a/lib/theme-loader.ts b/lib/theme-loader.ts
index c643299b..0e49d6ca 100644
--- a/lib/theme-loader.ts
+++ b/lib/theme-loader.ts
@@ -91,7 +91,7 @@ export function removeThemeCSS(): void {
 }
 
 /**
- * Inject a theme's *skin* CSS — component-level overrides shipped by Theme
+ * Inject a theme's *skin* CSS - component-level overrides shipped by Theme
  * API v2 themes via `skin.css`. Lives in a separate `<style>` tag so it can
  * be removed cleanly without touching the colour-token block, and is placed
  * AFTER the colour block so component rules win specificity.
@@ -124,7 +124,7 @@ export function removeThemeSkinCSS(): void {
 }
 
 /**
- * Sanitize a theme *skin* — looser than `sanitizeThemeCSS` because skins
+ * Sanitize a theme *skin* - looser than `sanitizeThemeCSS` because skins
  * intentionally target real component selectors (toolbars, lists, buttons),
  * not just `:root`/`.dark`. The same script-injection / external-resource
  * prohibitions still apply.
diff --git a/package-lock.json b/package-lock.json
index d4443ca0..1ff9d2ee 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "bulwark-webmail",
-  "version": "1.5.2",
+  "version": "1.5.3",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "bulwark-webmail",
-      "version": "1.5.2",
+      "version": "1.5.3",
       "license": "AGPL-3.0-only",
       "dependencies": {
         "@tanstack/react-virtual": "^3.13.24",
diff --git a/package.json b/package.json
index e8b18809..b96e552f 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "bulwark-webmail",
-  "version": "1.5.2",
+  "version": "1.5.3",
   "description": "Bulwark Webmail - a modern webmail client built for Stalwart Mail Server",
   "author": "Bulwark Webmail <bulwark@rbm.systems>",
   "license": "AGPL-3.0-only",
diff --git a/stores/theme-store.ts b/stores/theme-store.ts
index 8b1e25de..a737dc89 100644
--- a/stores/theme-store.ts
+++ b/stores/theme-store.ts
@@ -473,7 +473,7 @@ export const useThemeStore = create<ThemeState>()(
  *
  * Fires the `themeHooks.onThemeBeforeApply` transform hook so plugins can
  * post-process the CSS (e.g. inject extra `@font-face` rules or override
- * specific tokens). The hook is fire-and-forget — we inject the original
+ * specific tokens). The hook is fire-and-forget - we inject the original
  * CSS synchronously first to avoid a flash, then re-inject the transformed
  * version once handlers settle.
  *