diff --git a/Logic/FeatureSource/Actors/SaveTileToLocalStorageActor.ts b/Logic/FeatureSource/Actors/SaveTileToLocalStorageActor.ts
index 331168bb8e..22e6a7ba81 100644
--- a/Logic/FeatureSource/Actors/SaveTileToLocalStorageActor.ts
+++ b/Logic/FeatureSource/Actors/SaveTileToLocalStorageActor.ts
@@ -7,7 +7,8 @@ import {FeatureSourceForLayer} from "../FeatureSource";
 
 export default class SaveTileToLocalStorageActor {
     public static readonly storageKey: string = "cached-features";
-
+    public static readonly formatVersion : string = "1"
+    
     constructor(source: FeatureSourceForLayer, tileIndex: number) {
         source.features.addCallbackAndRunD(features => {
             const key = `${SaveTileToLocalStorageActor.storageKey}-${source.layer.layerDef.id}-${tileIndex}`
@@ -20,6 +21,7 @@ export default class SaveTileToLocalStorageActor {
             try {
                 localStorage.setItem(key, JSON.stringify(features));
                 localStorage.setItem(key + "-time", JSON.stringify(now))
+                localStorage.setItem(key+"-format", SaveTileToLocalStorageActor.formatVersion)
             } catch (e) {
                 console.warn("Could not save the features to local storage:", e)
             }
diff --git a/Logic/FeatureSource/TiledFeatureSource/TiledFromLocalStorageSource.ts b/Logic/FeatureSource/TiledFeatureSource/TiledFromLocalStorageSource.ts
index 4b578b7da2..3ad933d7e4 100644
--- a/Logic/FeatureSource/TiledFeatureSource/TiledFromLocalStorageSource.ts
+++ b/Logic/FeatureSource/TiledFeatureSource/TiledFromLocalStorageSource.ts
@@ -32,8 +32,18 @@ public tileFreshness : Map<number, Date> = new Map<number, Date>()
 
         console.debug("Layer", layer.layerDef.id, "has following tiles in available in localstorage", indexes.map(i => Tiles.tile_from_index(i).join("/")).join(", "))
         for (const index of indexes) {
-            const prefix = SaveTileToLocalStorageActor.storageKey + "-" + layer.layerDef.id + "-" +index+"-time";
-            const data = Number(localStorage.getItem(prefix))
+            
+            const prefix = SaveTileToLocalStorageActor.storageKey + "-" + layer.layerDef.id + "-" +index;
+            const version = localStorage.getItem(prefix+"-format")
+            if(version === undefined || version !== SaveTileToLocalStorageActor.formatVersion){
+                // Invalid version! Remove this tile from local storage
+                localStorage.removeItem(prefix)
+                undefinedTiles.add(index)
+                console.log("Dropped old format tile", prefix)
+                continue
+            }
+            
+            const data = Number(localStorage.getItem(prefix+"-time"))
             const freshness = new Date()
             freshness.setTime(data)
             this.tileFreshness.set(index, freshness)
diff --git a/assets/themes/cyclestreets/cyclestreets.json b/assets/themes/cyclestreets/cyclestreets.json
index 45ad1a90c0..39f75ac78e 100644
--- a/assets/themes/cyclestreets/cyclestreets.json
+++ b/assets/themes/cyclestreets/cyclestreets.json
@@ -35,6 +35,10 @@
   "startLon": 3.2228,
   "maintainer": "MapComplete",
   "widenfactor": 2,
+  "clustering": {
+    "maxZoom": 12,
+    "minNeededElements": 200
+  },
   "roamingRenderings": [
     {
       "question": {