diff --git a/src/c3nav/editor/models/changeset.py b/src/c3nav/editor/models/changeset.py
index 7eef6107..5f9a6670 100644
--- a/src/c3nav/editor/models/changeset.py
+++ b/src/c3nav/editor/models/changeset.py
@@ -681,7 +681,7 @@ class ChangeSet(models.Model):
 
     @property
     def cache_key_by_changes(self):
-        return ':'.join(('editor:changeset', str(self.pk), MapUpdate.cache_key(), self.last_change_cache_key))
+        return ':'.join(('editor:changeset', str(self.pk), MapUpdate.current_cache_key(), self.last_change_cache_key))
 
     def get_absolute_url(self):
         if self.pk is None:
diff --git a/src/c3nav/mapdata/models/base.py b/src/c3nav/mapdata/models/base.py
index d0c9b13b..1303ef53 100644
--- a/src/c3nav/mapdata/models/base.py
+++ b/src/c3nav/mapdata/models/base.py
@@ -80,7 +80,7 @@ class BoundsMixin(SerializableMixin, models.Model):
 
     @classmethod
     def max_bounds(cls):
-        cache_key = 'mapdata:max_bounds:%s:%s' % (cls.__name__, MapUpdate.cache_key())
+        cache_key = 'mapdata:max_bounds:%s:%s' % (cls.__name__, MapUpdate.current_cache_key())
         result = cache.get(cache_key, None)
         if result is not None:
             return result
diff --git a/src/c3nav/mapdata/models/update.py b/src/c3nav/mapdata/models/update.py
index 386c8288..409273b9 100644
--- a/src/c3nav/mapdata/models/update.py
+++ b/src/c3nav/mapdata/models/update.py
@@ -34,8 +34,12 @@ class MapUpdate(models.Model):
             cache.set('mapdata:last_update', (last_update.pk, last_update.datetime), 900)
         return last_update.pk, last_update.datetime
 
+    @property
+    def cache_key(self):
+        return int_to_base36(self.pk)+'_'+int_to_base36(int(make_naive(self.datetime).timestamp()))
+
     @classmethod
-    def cache_key(cls):
+    def current_cache_key(cls):
         pk, dt = cls.last_update()
         return int_to_base36(pk)+'_'+int_to_base36(int(make_naive(dt).timestamp()))
 
diff --git a/src/c3nav/mapdata/render/base.py b/src/c3nav/mapdata/render/base.py
index 5ae38fa3..7e4044b8 100644
--- a/src/c3nav/mapdata/render/base.py
+++ b/src/c3nav/mapdata/render/base.py
@@ -230,7 +230,7 @@ class LevelGeometries:
 
 def get_level_render_data(level):
     cache_key = 'mapdata:level_render_data:%s:%s' % (str(level.pk if isinstance(level, Level) else level),
-                                                     MapUpdate.cache_key())
+                                                     MapUpdate.current_cache_key())
     result = cache.get(cache_key, None)
     if result is not None:
         return result
diff --git a/src/c3nav/mapdata/tasks.py b/src/c3nav/mapdata/tasks.py
index 0274a91c..67b55783 100644
--- a/src/c3nav/mapdata/tasks.py
+++ b/src/c3nav/mapdata/tasks.py
@@ -8,7 +8,7 @@ from c3nav.celery import app
 @app.task()
 def delete_old_cached_tiles(*args, **kwargs):
     from c3nav.mapdata.models import MapUpdate
-    cache_key = MapUpdate.cache_key()
+    cache_key = MapUpdate.current_cache_key()
 
     for folder in os.listdir(settings.TILES_ROOT):
         if folder == cache_key:
diff --git a/src/c3nav/mapdata/views.py b/src/c3nav/mapdata/views.py
index 2b6b21f9..de960f9f 100644
--- a/src/c3nav/mapdata/views.py
+++ b/src/c3nav/mapdata/views.py
@@ -32,7 +32,7 @@ def tile(request, level, zoom, x, y, format):
 
     renderer = SVGRenderer(level, miny, minx, maxy, maxx, scale=2**zoom, user=request.user)
 
-    update_cache_key = MapUpdate.cache_key()
+    update_cache_key = MapUpdate.current_cache_key()
     access_cache_key = renderer.access_cache_key
     etag = update_cache_key+'_'+access_cache_key