diff --git a/Alpine/APKGBUILD b/Alpine/APKGBUILD
index 53435c1..a3e474e 100644
--- a/Alpine/APKGBUILD
+++ b/Alpine/APKGBUILD
@@ -10,7 +10,7 @@
 # .apk file extension == .tar.gz file extension
 
 pkgname=py3-nextcast
-pkgver=0.0.3
+pkgver=0.0.4
 pkgrel=1
 pkgdesc="Nextcloud Podcast Client"
 url="https://git.privacy1st.de/langfingaz/nextcast"
diff --git a/README.md b/README.md
index b160916..114afde 100644
--- a/README.md
+++ b/README.md
@@ -55,7 +55,7 @@ cp Alpine/APKGBUILD ~/.local/var/pmbootstrap/cache_git/pmaports/main/py3-nextcas
 pmbootstrap apkbuild_parse py3-nextcast
 pmbootstrap checksum py3-nextcast
 pmbootstrap build --arch aarch64 py3-nextcast
-#=> build x86_64/py3-nextcast-0.0.3-r1.apk
+#=> build x86_64/py3-nextcast-0.0.4-r1.apk
 ```
 
 ```shell
@@ -63,8 +63,8 @@ pmbootstrap shutdown
 ```
 
 ```shell
-ls ~/.local/var/pmbootstrap/packages/edge/x86_64/py3-nextcast-0.0.3-r1.apk
-ls ~/.local/var/pmbootstrap/packages/edge/x86_64/py3-nextcast-pyc-0.0.3-r1.apk
+ls ~/.local/var/pmbootstrap/packages/edge/x86_64/py3-nextcast-0.0.4-r1.apk
+ls ~/.local/var/pmbootstrap/packages/edge/x86_64/py3-nextcast-pyc-0.0.4-r1.apk
 ```
 
 Sideload to your postmarketOS phone:
@@ -74,3 +74,8 @@ Sideload to your postmarketOS phone:
 ```shell
 pmbootstrap sideload --host yodaEnchilada --user yoda --arch aarch64 --install-key py3-nextcast
 ```
+
+## TODOs
+
+- [ ] If action refers unknown episode/podcast, create it.
+- [ ] Executable to update local list of podcasts and episodes.
diff --git a/setup.cfg b/setup.cfg
index 076df22..26561dc 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -3,7 +3,7 @@
 
 [metadata]
 name = nextcast
-version = 0.0.3
+version = 0.0.4
 author = Daniel Langbein
 author_email = daniel@systemli.org
 description = Nextcloud Podcast Client
diff --git a/src/nextcast/app_play_episode.py b/src/nextcast/app_play_episode.py
index c14d7bb..e9a5752 100755
--- a/src/nextcast/app_play_episode.py
+++ b/src/nextcast/app_play_episode.py
@@ -7,6 +7,7 @@ from typing import Callable
 from nextcast import mpv
 from nextcast.cli_gui import list_selection, CancelButton, TopButton
 from nextcast.log import Log
+from nextcast.nextcloud import LoginExpired
 from nextcast.podcast import User, Episode, Podcast
 from nextcast.user_manager import UserManager
 
@@ -36,6 +37,10 @@ def podcast_loop(prev: Callable, user: User) -> None:
             title='Select podcast',
             top_buttons=[back_str],
         )
+    except LoginExpired as _e:
+        Log.error(f'Nextcloud login of user {user.user_id} expired. Please re-login.')
+        UserManager.logout(user)
+        exit()
     except CancelButton as _e:
         exit()
     except TopButton as e:
diff --git a/src/nextcast/app_resume_playback.py b/src/nextcast/app_resume_playback.py
index 2af3389..3ab6130 100755
--- a/src/nextcast/app_resume_playback.py
+++ b/src/nextcast/app_resume_playback.py
@@ -3,6 +3,7 @@
 from nextcast import mpv
 from nextcast.cli_gui import list_selection, CancelButton
 from nextcast.log import Log
+from nextcast.nextcloud import LoginExpired
 from nextcast.user_manager import UserManager
 
 
@@ -12,7 +13,12 @@ def main():
     Log.config(pause_on_error=True)
 
     user = UserManager.from_interaction()
-    episodes = user.get_episodes()
+    try:
+        episodes = user.get_episodes()
+    except LoginExpired as _e:
+        Log.error(f'Nextcloud login of user {user.user_id} expired. Please re-login.')
+        UserManager.logout(user)
+        exit()
 
     # Paused episodes.
     pauseds = [episode for episode in episodes
diff --git a/src/nextcast/nextcloud.py b/src/nextcast/nextcloud.py
index b7defe5..ff38602 100644
--- a/src/nextcast/nextcloud.py
+++ b/src/nextcast/nextcloud.py
@@ -1,6 +1,7 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 import json
+import socket
 import time
 import webbrowser
 from datetime import datetime, timedelta
@@ -110,6 +111,10 @@ class EpisodeAction:
         return json.dumps(self.to_json())
 
 
+class LoginExpired(Exception):
+    status_code = 401
+
+
 class NextcloudApi:
     @classmethod
     def login(cls, domain: str) -> tuple[str, str, str]:
@@ -117,7 +122,11 @@ class NextcloudApi:
         Login flow documentation:
         https://docs.nextcloud.com/server/latest/developer_manual/client_apis/LoginFlow/index.html
         """
-        r = requests.post(f'https://{domain}/index.php/login/v2')
+        # Set human-readable user agent when logging in.
+        # This string is displayed in the Nextcloud web interface under "Device & Sessions".
+        hostname: str = socket.gethostname()
+        headers = {'User-Agent': f'nextcast@{hostname}'}
+        r = requests.post(f'https://{domain}/index.php/login/v2', headers=headers)
         assert r.status_code == 200
         content = json.loads(r.text)
         webbrowser.open(content['login'], new=0, autoraise=True)
@@ -149,12 +158,16 @@ class NextcloudApi:
         https://github.com/thrillfall/nextcloud-gpodder/blob/main/README.md#subscription
 
         :return: The URLs of the subscribed podcast feeds. Example: 'https://logbuch-netzpolitik.de/feed/opus'
+        :raises LoginExpired:
         """
         url = f'{server}/apps/gpoddersync/subscriptions'
         Log.info(f'Downloading {url} ...')
         # auth parameter: https://requests.readthedocs.io/en/latest/user/authentication/#basic-authentication
         r = requests.get(url, auth=(login_name, app_password))
-        assert r.status_code == 200
+        if r.status_code == LoginExpired.status_code:
+            raise LoginExpired()
+        else:
+            assert r.status_code == 200, r.status_code
         content = json.loads(r.text)
         return content['add']
 
@@ -188,6 +201,8 @@ class NextcloudApi:
             -> tuple[datetime, list[EpisodeAction]]:
         """
         https://github.com/thrillfall/nextcloud-gpodder/blob/main/README.md#episode-action
+
+        :raises LoginExpired:
         """
         if types is None:
             types = [ea_type for ea_type in EpisodeActionType]
@@ -196,7 +211,10 @@ class NextcloudApi:
         Log.info(f'Downloading {url} ...')
         # auth parameter: https://requests.readthedocs.io/en/latest/user/authentication/#basic-authentication
         r = requests.get(url, auth=(login_name, app_password))
-        assert r.status_code == 200
+        if r.status_code == LoginExpired.status_code:
+            raise LoginExpired()
+        else:
+            assert r.status_code == 200, r.status_code
         content = json.loads(r.text)
 
         timestamp = datetime_util.from_timestamp(content['timestamp'])
@@ -208,6 +226,9 @@ class NextcloudApi:
     @classmethod
     def push_episode_actions(cls, server: str, login_name: str, app_password: str,
                              actions: list[EpisodeAction]) -> None:
+        """
+        :raises LoginExpired:
+        """
         data = [action.to_json() for action in actions]
 
         url = f'{server}/apps/gpoddersync/episode_action/create'
@@ -216,7 +237,10 @@ class NextcloudApi:
         headers = {'Content-type': 'application/json'}
         r = requests.post(url, auth=(login_name, app_password),
                           headers=headers, data=data_str)
-        assert r.status_code == 200
+        if r.status_code == LoginExpired.status_code:
+            raise LoginExpired()
+        else:
+            assert r.status_code == 200, r.status_code
 
 
 if __name__ == '__main__':
diff --git a/src/nextcast/user_manager.py b/src/nextcast/user_manager.py
index 015cebf..fee4423 100644
--- a/src/nextcast/user_manager.py
+++ b/src/nextcast/user_manager.py
@@ -35,6 +35,11 @@ class UserManager:
         cls._get_content()[user.user_id] = user.app_password
         json_util.write_credentials(cls._get_content())
 
+    @classmethod
+    def remove_from_disk(cls, user: User) -> None:
+        cls._get_content().pop(user.user_id, None)
+        json_util.write_credentials(cls._get_content())
+
     @classmethod
     def from_interaction(cls) -> User:
         """
@@ -84,3 +89,7 @@ class UserManager:
         cls.add_to_disk(user)
 
         return user
+
+    @classmethod
+    def logout(cls, user: User):
+        cls.remove_from_disk(user)