diff --git a/src/common/optionsPrototype.json5 b/src/common/optionsPrototype.json5
index 5866b0e..6b6e01b 100644
--- a/src/common/optionsPrototype.json5
+++ b/src/common/optionsPrototype.json5
@@ -124,6 +124,16 @@
     context: 'options',
     killSwitchType: 'option',
   },
+  'interopthreadpage': {
+    defaultValue: false,
+    context: 'options',
+    killSwitchType: 'option',
+  },
+  'interopthreadpage_mode': {
+    defaultValue: 'previous',
+    context: 'options',
+    killSwitchType: 'ignore',
+  },
 
   // Experiments:
   'workflows': {
@@ -136,6 +146,11 @@
     context: 'experiments',
     killSwitchType: 'experiment',
   },
+  'nestedreplies': {
+    defaultValue: false,
+    context: 'experiments',
+    killSwitchType: 'experiment',
+  },
 
   // Internal options:
   'ccdarktheme_switch_enabled': {
diff --git a/src/common/specialOptions.json5 b/src/common/specialOptions.json5
index 37b69fa..58d330c 100644
--- a/src/common/specialOptions.json5
+++ b/src/common/specialOptions.json5
@@ -2,4 +2,5 @@
   'profileindicatoralt_months',
   'ccdarktheme_mode',
   'ccdarktheme_switch_enabled',
+  'interopthreadpage_mode',
 ]