diff --git a/ictv/database.py b/ictv/database.py
index 955f0a0..dec1fe0 100644
--- a/ictv/database.py
+++ b/ictv/database.py
@@ -109,7 +109,11 @@ def update_database():
         DBVersion(version=database_version)
     db_version = DBVersion.select().getOne().version
     if db_version < 1:
-        # Do upgrade stuff
+        print('Updating database to version %d' % 1)
+        column_sql = Asset.sqlmeta.getColumns()['last_update'].sqliteCreateSQL()
+        table = PluginChannel.sqlmeta.table
+        assert conn.queryOne('ALTER TABLE %s ADD %s' % (table, column_sql)) is None
+        db_version = 1
         pass
     DBVersion.select().getOne().set(version=db_version)
 
diff --git a/ictv/models/asset.py b/ictv/models/asset.py
index c04a3f7..fca8f58 100644
--- a/ictv/models/asset.py
+++ b/ictv/models/asset.py
@@ -37,6 +37,7 @@ class Asset(ICTVObject):
     extension = StringCol(default=None)
     file_size = BigIntCol(default=None)  # File size in kilobytes
     created = DateTimeCol(default=DateTimeCol.now)
+    last_update = DateTimeCol(default=DateTimeCol.now)
     last_reference = DateTimeCol(default=DateTimeCol.now)
     in_flight = BoolCol(default=False)  # Is this asset being cached at the moment
     is_cached = BoolCol(default=False)  # Is this asset a cached asset from CacheManager
@@ -68,4 +69,5 @@ def on_asset_deleted(instance, kwargs):
         # TODO: log message to app.log
         print(e)
 
+
 listen(on_asset_deleted, Asset, RowDestroyedSignal)
diff --git a/ictv/storage/cache_manager.py b/ictv/storage/cache_manager.py
index 0def84d..ff495e7 100644
--- a/ictv/storage/cache_manager.py
+++ b/ictv/storage/cache_manager.py
@@ -77,6 +77,18 @@ def cache_file_at_url(self, url):
                 CacheManager._get_lock(cache_asset_hash, blocking=True)
                 CacheManager._release_lock(cache_asset_hash)
                 asset = Asset.selectBy(plugin_channel=self.channel_id, filename=filename, is_cached=True).getOne(None)
+        elif datetime.datetime.now() - asset.last_update > datetime.timedelta(minutes=5):
+            logger.debug('Refreshing asset %d at url %s', asset.id, url)
+            CacheManager._get_lock(cache_asset_hash, blocking=True)
+            asset.last_update = datetime.datetime.now()
+            try:
+                self.download_manager.clear_pending_task_for_asset(asset.id)
+                self.download_manager.enqueue_asset(asset)
+            except (URLError, OSError):
+                logger.warning('Exception encountered when attempting to update file at url %s', url, exc_info=True)
+                CacheManager._release_lock(cache_asset_hash)
+                return None
+            CacheManager._release_lock(cache_asset_hash)
         return asset
 
     _name_to_lock = {}
diff --git a/ictv/storage/download_manager.py b/ictv/storage/download_manager.py
index a319ce4..2b6f6fe 100644
--- a/ictv/storage/download_manager.py
+++ b/ictv/storage/download_manager.py
@@ -20,6 +20,7 @@
 #    along with ICTV.  If not, see <http://www.gnu.org/licenses/>.
 
 import asyncio
+from datetime import datetime
 from queue import Queue
 
 import os
@@ -27,6 +28,7 @@
 
 import aiohttp
 import magic
+import werkzeug.http
 from sqlobject import sqlhub
 
 from ictv.common import get_root_path
@@ -51,7 +53,9 @@ def enqueue_asset(self, asset):
         if asset.id not in self._pending_tasks:
             def enqueue_post_process_asset(task):
                 mime_type, file_size = task.result()
-                self._post_process_queue.put((mime_type, file_size, asset))
+                asset.created = datetime.now()
+                if mime_type is not None and file_size is not None:
+                    self._post_process_queue.put((mime_type, file_size, asset))
 
             task = asyncio.run_coroutine_threadsafe(DownloadManager._cache_asset(asset.filename + (asset.extension or ''), asset.path), self._loop)
             asset.in_flight = True
@@ -66,6 +70,11 @@ def get_pending_task_for_asset(self, asset_id):
         """ Returns the corresponding task to the given asset. """
         return self._pending_tasks[asset_id]
 
+    def clear_pending_task_for_asset(self, asset_id):
+        """ Resets the status of the task associated with the given asset. """
+        if self.has_pending_task_for_asset(asset_id):
+            del self._pending_tasks[asset_id]
+
     def stop(self):
         if self._loop.is_running():
             self._loop.call_soon_threadsafe(self._loop.stop)
@@ -74,7 +83,7 @@ def stop(self):
     def _run_loop(self):
         sqlhub.threadConnection = SQLObjectThreadConnection.get_conn()
         asyncio.set_event_loop(self._loop)
-        if not self._loop.is_closed():
+        if not self._loop.is_closed() and not self._loop.is_running():
             self._loop.run_forever()
             self._loop.close()
 
@@ -88,13 +97,25 @@ def _post_process_asset(self):
 
     @staticmethod
     async def _cache_asset(url, path):
-        content = await DownloadManager._get_content(url)
-        with open(os.path.join(get_root_path(), path), 'wb') as f:
+        file_path = os.path.join(get_root_path(), path)
+        if os.path.exists(file_path):
+            last_modified = werkzeug.http.http_date(os.stat(file_path).st_mtime)
+        else:
+            last_modified = None
+        content = await DownloadManager._get_content(url, last_modified)
+        if not content:
+            return None, None
+        with open(file_path, 'wb') as f:
             f.write(content)
         return magic.from_buffer(content, mime=True), len(content)
 
     @staticmethod
-    async def _get_content(url):
+    async def _get_content(url, last_modified=None):
         async with aiohttp.ClientSession() as session:
-            async with session.get(url) as resp:
-                return await resp.read()
+            async with session.get(url, headers={'If-Modified-Since': last_modified} if last_modified else {}) as resp:
+                if resp.status is 304:
+                    return None
+                elif resp.status is 200:
+                    return await resp.read()
+                else:
+                    return None
diff --git a/ictv/tests/test_code.py b/ictv/tests/test_code.py
index 4dea7a5..8dc2ddb 100644
--- a/ictv/tests/test_code.py
+++ b/ictv/tests/test_code.py
@@ -22,7 +22,10 @@
 import os
 import random
 import string
-from datetime import date, datetime
+import tempfile
+import subprocess
+from datetime import date, datetime, timedelta
+from time import sleep
 
 import web
 from nose.tools import *
@@ -32,7 +35,7 @@
 from ictv.common import get_root_path
 from ictv.models.asset import Asset
 from ictv.models.building import Building
-from ictv.models.channel import PluginChannel, ChannelBundle
+from ictv.models.channel import PluginChannel, ChannelBundle, Channel
 from ictv.models.plugin import Plugin
 from ictv.models.plugin_param_access_rights import PluginParamAccessRights
 from ictv.models.role import UserPermissions, Role
@@ -43,6 +46,8 @@
 from ictv.common.feedbacks import get_feedbacks, add_feedback, get_next_feedbacks, ImmediateFeedback
 from ictv.common.json_datetime import DateTimeDecoder, DateTimeEncoder
 from ictv.plugin_manager import plugin_manager
+from ictv.storage.cache_manager import CacheManager
+from ictv.storage.download_manager import DownloadManager
 from ictv.tests import ICTVTestCase, FakePluginTestCase
 
 
@@ -532,3 +537,45 @@ def common_utils(self):
         add_feedback(type=1, message="This is a test feedback from the unit test")
         assert_true(feedbacks_has_type(type=1, feedbacks=get_next_feedbacks()))
         assert_false(feedbacks_has_type(type="NOTESTINGFEEDBACK", feedbacks=get_next_feedbacks()))
+
+
+class CacheManagerTest(ICTVTestCase):
+    def runTest_(self):
+        """ Tests the cache mechanism. """
+        dm = DownloadManager()
+
+        c = PluginChannel(name='Channel', subscription_right='public', secret='abcdef', plugin=Plugin(name='channel_plugin', activated='no'))
+        cm = CacheManager(c, dm)
+        port = 64080
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            os.chdir(tmpdir)
+            p = subprocess.Popen(['python3', '-m', 'http.server', '--b', '127.0.0.1', str(port)])
+            sleep(2)
+
+            with open(os.path.join(tmpdir, 'a.txt'), 'w') as f:
+                f.write('ABCDEFG')
+
+            a = cm.cache_file_at_url('http://127.0.0.1:%d/a.txt' % port)
+            sleep(1)
+
+            assert a.file_size == 7
+            a.last_update -= timedelta(minutes=10)
+
+            last_update = a.created
+            with open(os.path.join(tmpdir, 'a.txt'), 'w') as f:  # There is no touch in Python
+                f.write('ABCDEFG')
+
+            a = cm.cache_file_at_url('http://127.0.0.1:%d/a.txt' % port)
+            sleep(1)
+            assert a.created > last_update
+            last_update = a.created
+
+            a = cm.cache_file_at_url('http://127.0.0.1:%d/a.txt' % port)
+            sleep(1)
+            assert a.created == last_update
+
+            os.unlink(os.path.join(get_root_path()), a.path)
+            p.kill()
+
+        dm.stop()
diff --git a/setup.py b/setup.py
index 2de0792..116be9e 100644
--- a/setup.py
+++ b/setup.py
@@ -39,7 +39,7 @@
     description='ICTV is a simple content management system for digital signage on multiple screens.',
     install_requires=['sqlobject', 'typing', 'icalendar', 'pyyaml', 'urllib3', 'web.py>=0.40.dev0',
                       'yamlordereddictloader', 'pyquery', 'BeautifulSoup4', 'python-magic', 'aiohttp', 'wand',
-                      'feedparser', 'qrcode', 'selenium', 'python3-saml', 'pymediainfo'],
+                      'feedparser', 'qrcode', 'selenium', 'python3-saml', 'pymediainfo', 'werkzeug'],
     setup_requires=['pytest-runner', 'pytest-env'] if not is_running_on_macos else [],
     tests_require=['pytest', 'pytest-xdist', 'pytest-cov', 'paste', 'nose', 'coverage<5'],
     dependency_links=['https://github.com/formencode/formencode.git#egg=FormEncode'],