diff --git a/README.md b/README.md
index 13b12e9..4b78e8c 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # Theme Song Booth
 
-**Version:** `v0.4.4`
+**Version:** `v0.4.5`
 
 A Flask web app for a convention booth where visitors request a custom AI-generated theme song, the operator manages the queue, and the final MP3(s) are delivered by email after payment.
 
diff --git a/VERSION b/VERSION
index 6f2743d..0bfccb0 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.4.4
+0.4.5
diff --git a/app.py b/app.py
index f200833..2c0f3b9 100644
--- a/app.py
+++ b/app.py
@@ -360,8 +360,9 @@ def sign_prompt_callback(rid, expires_at=None):
     """
     secret = current_app.config['SECRET_KEY'].encode()
     if expires_at is None:
-        # Default expiry: 1 hour.
-        expires_at = int(time.time()) + 3600
+        # Default expiry: 7 days, so operators have plenty of time to copy the
+        # callback URL into Hermes and for Hermes to POST back.
+        expires_at = int(time.time()) + 7 * 24 * 3600
     payload = f"{rid}:{expires_at}"
     sig = hmac.new(secret, payload.encode(), hashlib.sha256).hexdigest()[:16]
     return f"{rid}:{expires_at}:{sig}"