diff --git a/artifacts/tx-os/src/index.css b/artifacts/tx-os/src/index.css
index 19678d83..7226aeb7 100644
--- a/artifacts/tx-os/src/index.css
+++ b/artifacts/tx-os/src/index.css
@@ -235,6 +235,8 @@
 .icon-tile-orange { background: linear-gradient(135deg, #FDBA74, #F59E0B); }
 .icon-tile-pink   { background: linear-gradient(135deg, #F9A8D4, #EC4899); }
 .icon-tile-teal   { background: linear-gradient(135deg, #5EEAD4, #14B8A6); }
+.icon-tile-red    { background: linear-gradient(135deg, #FCA5A5, #EF4444); }
+.icon-tile-yellow { background: linear-gradient(135deg, #FDE68A, #EAB308); }
 
 /* Top bar variant — flat very-light glass, no heavy border */
 .topbar-glass {
diff --git a/artifacts/tx-os/src/pages/home.tsx b/artifacts/tx-os/src/pages/home.tsx
index 247b525f..8f5d42c3 100644
--- a/artifacts/tx-os/src/pages/home.tsx
+++ b/artifacts/tx-os/src/pages/home.tsx
@@ -81,6 +81,15 @@ function resolveIcon(name: string): LucideIcon {
 
 function gradientForColor(color: string): string {
   const c = (color ?? "").toLowerCase();
+  // #603: each built-in app now ships with a distinct hue so the four
+  // default tiles (Notes/Services/Meetings/Admin) read as four different
+  // colours instead of three blues + one orange. New patterns added for
+  // yellow (#eab308 / facc15) and red (#ef4444 / dc2626), and the green
+  // branch already accepts the new #22c55e Meetings colour. The purple
+  // branch stays for any admin who manually picks a purple via the
+  // Apps editor, but no seeded row uses it any more.
+  if (c.includes("ef4444") || c.includes("dc2626") || c.includes("red")) return "icon-tile-red";
+  if (c.includes("eab308") || c.includes("facc15") || c.includes("yellow")) return "icon-tile-yellow";
   if (c.includes("a855f7") || c.includes("8b5cf6") || c.includes("purple") || c.includes("violet")) return "icon-tile-purple";
   if (c.includes("10b981") || c.includes("22c55e") || c.includes("green") || c.includes("emerald")) return "icon-tile-green";
   if (c.includes("f59e0b") || c.includes("f97316") || c.includes("orange") || c.includes("amber")) return "icon-tile-orange";
diff --git a/scripts/package.json b/scripts/package.json
index 5b266007..3f99d764 100644
--- a/scripts/package.json
+++ b/scripts/package.json
@@ -8,6 +8,7 @@
     "seed": "tsx ./src/seed.ts",
     "remove-chat": "tsx ./src/remove-chat.ts",
     "disable-deprecated-apps": "tsx ./src/disable-deprecated-apps.ts",
+    "update-app-colors": "tsx ./src/update-app-colors.ts",
     "typecheck": "tsc -p tsconfig.json --noEmit",
     "test": "node --test 'tests/**/*.test.mjs'"
   },
diff --git a/scripts/redeploy.sh b/scripts/redeploy.sh
index 9bf6de25..9ab5e194 100755
--- a/scripts/redeploy.sh
+++ b/scripts/redeploy.sh
@@ -72,13 +72,13 @@ fi
 step() { echo; echo "==> $*"; }
 
 if [ "$PULL" -eq 1 ]; then
-  step "1/4  git pull"
+  step "1/6  git pull"
   git pull --ff-only
 else
-  step "1/4  git pull (skipped via --no-pull)"
+  step "1/6  git pull (skipped via --no-pull)"
 fi
 
-step "2/5  docker compose build api web  (rebuilds SPA + API images)"
+step "2/6  docker compose build api web  (rebuilds SPA + API images)"
 # Stamp the API image with the current git SHA + UTC build time so the
 # admin "System Updates" panel shows visible proof that the new image
 # is actually running (instead of the old, hand-edited version.json).
@@ -88,14 +88,23 @@ export BUILD_DATE="$(date -u +%Y-%m-%dT%H:%M:%SZ)"
 echo "[redeploy]   GIT_SHA=$GIT_SHA  BUILD_DATE=$BUILD_DATE"
 "${DC[@]}" build api web
 
-step "3/5  docker compose run --rm migrate  (schema push + tolerant seed)"
+step "3/6  docker compose run --rm migrate  (schema push + tolerant seed)"
 "${DC[@]}" run --rm migrate
 
-step "4/5  explicit seed pass (fails hard on seed regressions)"
+step "4/6  explicit seed pass (fails hard on seed regressions)"
 "${DC[@]}" run --rm --no-deps --entrypoint "" migrate \
   pnpm --filter @workspace/scripts run seed
 
-step "5/5  docker compose up -d  (restart with the new images)"
+step "5/6  one-shot data migrations (idempotent)"
+# #603: bump seeded app tile colours on existing installs. The seed
+# step above uses onConflictDoNothing for `slug`, so already-seeded
+# rows keep their old colours forever without this. The script only
+# touches rows that still hold the OLD default — admin customisations
+# from the Apps editor are left alone.
+"${DC[@]}" run --rm --no-deps --entrypoint "" migrate \
+  pnpm --filter @workspace/scripts run update-app-colors
+
+step "6/6  docker compose up -d  (restart with the new images)"
 "${DC[@]}" up -d
 
 echo
diff --git a/scripts/src/seed.ts b/scripts/src/seed.ts
index c3dbb0f7..37be6844 100644
--- a/scripts/src/seed.ts
+++ b/scripts/src/seed.ts
@@ -230,7 +230,11 @@ async function main() {
       descriptionEn: "Manage your notifications and alerts",
       iconName: "Bell",
       route: "/notifications",
-      color: "#8b5cf6",
+      // #603: was #8b5cf6 (purple). Switched to cyan so no seeded app
+      // ships with a purple tile. Existing installs are migrated by
+      // scripts/src/update-app-colors.ts (only rows still on the old
+      // default are touched — admin customisations are preserved).
+      color: "#06b6d4",
       // #571: ship the Notifications app DISABLED by default so fresh
       // installs don't surface a redundant tile alongside the bell icon
       // already in the top bar. The bell stays the canonical entry
@@ -313,7 +317,12 @@ async function main() {
       descriptionEn: "Schedule and track meetings",
       iconName: "CalendarClock",
       route: "/meetings",
-      color: "#0B1E3F",
+      // #603: was #0B1E3F (dark navy) which fell through to the default
+      // blue tile gradient, making Meetings indistinguishable from
+      // Admin/Notes on the home screen. Switched to green so the four
+      // default tiles are visually distinct. Existing installs are
+      // migrated by scripts/src/update-app-colors.ts.
+      color: "#22c55e",
       isActive: true,
       isSystem: false,
       sortOrder: 7,
diff --git a/scripts/src/update-app-colors.ts b/scripts/src/update-app-colors.ts
new file mode 100644
index 00000000..5a32f1ce
--- /dev/null
+++ b/scripts/src/update-app-colors.ts
@@ -0,0 +1,48 @@
+import { db, appsTable } from "@workspace/db";
+import { and, eq } from "drizzle-orm";
+
+// #603: One-shot migration that bumps the seeded app colours on
+// existing installs to the new #603 palette. The seed itself uses
+// `onConflictDoNothing` on `slug`, so previously-seeded rows would
+// otherwise keep their old hex values forever and continue to render
+// as three identical blue tiles on the home screen.
+//
+// Each update is gated on the row STILL holding the old default —
+// admins who customised an app colour from the Apps editor keep their
+// choice untouched.
+const MIGRATIONS: Array<{ slug: string; from: string; to: string }> = [
+  // Meetings: dark navy → green (was falling through to default blue).
+  { slug: "executive-meetings", from: "#0B1E3F", to: "#22c55e" },
+  // Notifications: purple → cyan (purple is no longer in the palette).
+  { slug: "notifications", from: "#8b5cf6", to: "#06b6d4" },
+];
+
+async function main(): Promise<void> {
+  console.log("Migrating app colours to the #603 palette...");
+  let touched = 0;
+  for (const m of MIGRATIONS) {
+    const updated = await db
+      .update(appsTable)
+      .set({ color: m.to })
+      .where(and(eq(appsTable.slug, m.slug), eq(appsTable.color, m.from)))
+      .returning({ slug: appsTable.slug, color: appsTable.color });
+    if (updated.length === 0) {
+      console.log(
+        `  - ${m.slug}: skipped (row missing or already customised)`,
+      );
+    } else {
+      touched += updated.length;
+      for (const row of updated) {
+        console.log(`  - ${row.slug}: color → ${row.color}`);
+      }
+    }
+  }
+  console.log(`Done. Rows updated: ${touched}.`);
+}
+
+main()
+  .catch((err) => {
+    console.error(err);
+    process.exit(1);
+  })
+  .finally(() => process.exit(0));