diff --git a/src/ext/conf/ExtConfPatches.js b/src/ext/conf/ExtConfPatches.js
new file mode 100644
index 0000000..a9d4701
--- /dev/null
+++ b/src/ext/conf/ExtConfPatches.js
@@ -0,0 +1,44 @@
+// How to use:
+// version: {ExtensionConf object, but only properties that get overwritten}
+
+const ExtensionConfPatch = {
+  '4.2.0': {
+    sites: {
+      "old.reddit.com" : {
+        type: 'testing',
+        DOM: {
+          player: {
+            manual: true,
+            useRelativeAncestor: false,
+            querySelectors: '.media-preview-content'
+          }
+        },
+        css: '',
+      },
+      "www.reddit.com" : {
+        type: 'testing',
+        DOM: {
+          player: {
+            manual: true,
+            useRelativeAncestor: false,
+            querySelectors: '.media-preview-content'
+          }
+        },
+        css: '',
+      },
+      "www.youtube.com" : {
+        DOM: {
+          player: {
+            manual: true,
+            querySelectors: "#movie_player, #player",
+            additionalCss: "",
+            useRelativeAncestor: false,
+            playerNodeCss: "",
+          }
+        }
+      },
+    }
+  }
+}
+
+export default ExtensionConfPatch;
\ No newline at end of file
diff --git a/src/ext/lib/ObjectCopy.js b/src/ext/lib/ObjectCopy.js
index 398d26e..705613b 100644
--- a/src/ext/lib/ObjectCopy.js
+++ b/src/ext/lib/ObjectCopy.js
@@ -46,6 +46,32 @@ class ObjectCopy {
     return out;
   }
 
+  static overwrite(existing, target){
+    for(var k in target) {
+      // if current key exist, replace it with existing value. Take no action otherwise.
+      if (existing[k]) {
+
+        // Types and constructors of objects must match. If they don't, we always use the new value.
+        if (typeof target[k] === typeof existing[k] && target[k].constructor === existing[k].constructor) {
+          
+          // objects are special, we need to check them recursively.
+          if(existing[k] && typeof existing[k] === 'object' && existing[k].constructor === Object ) {
+            if(Debug.debug && Debug.settings) {
+              console.log("[ObjectCopy::addNew] current key contains an object. Recursing!")
+            }
+
+            existing[k] = this.overwrite(existing[k], target[k]);
+          } else {
+            existing[k] = target[k];       
+          }
+        } else {
+          existing[k] = target[k];
+        }
+      }
+    }
+    return existing;
+  }
+
   static pruneUnused(existing, target, ignoreKeys) {
     // TODO: implement at some other date
     // existing: object that we have.
diff --git a/src/ext/lib/Settings.js b/src/ext/lib/Settings.js
index 21238eb..d935ed7 100644
--- a/src/ext/lib/Settings.js
+++ b/src/ext/lib/Settings.js
@@ -5,6 +5,7 @@ import ExtensionMode from '../../common/enums/extension-mode.enum';
 import ObjectCopy from '../lib/ObjectCopy';
 import Stretch from '../../common/enums/stretch.enum';
 import VideoAlignment from '../../common/enums/video-alignment.enum';
+import ExtensionConfPatch from '../conf/ExtConfPatches';
 
 
 
@@ -108,6 +109,7 @@ class Settings {
       if(Debug.debug) {
         console.log("[Settings::init] extension was saved with current version of ultrawidify (", this.version, "). Returning object as-is.");
       }
+
       return this.active;
     }
 
@@ -124,6 +126,9 @@ class Settings {
       this.active = JSON.parse(JSON.stringify(this.default));
     }
 
+    // in case settings in previous version contained a fucky wucky, we overwrite existing settings with a patch
+    ObjectCopy.overwrite(this.active, ExtensionConfPatch['4.2.0']);
+
     this.set(this.active);
     return this.active;
   }