diff --git a/README.md b/README.md
index dedaa01a..6df17635 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # Kaleidoscope-TopsyTurvy
 
-![status][st:stable] [![Build Status][travis:image]][travis:status]
+![status][st:experimental] [![Build Status][travis:image]][travis:status]
 
  [travis:image]: https://travis-ci.org/keyboardio/Kaleidoscope-TopsyTurvy.svg?branch=master
  [travis:status]: https://travis-ci.org/keyboardio/Kaleidoscope-TopsyTurvy
@@ -26,9 +26,9 @@ effects to, and use the plugin:
 // In the keymap:
 TOPSY(1), TOPSY(2), TOPSY(3)
 
-void setup () {
-  Kaleidoscope.use (&TopsyTurvy);
+KALEIDOSCOPE_INIT_PLUGINS(TopsyTurvy);
 
+void setup () {
   Kaleidoscope.setup ();
 }
 ```
diff --git a/examples/TopsyTurvy/TopsyTurvy.ino b/examples/TopsyTurvy/TopsyTurvy.ino
index ca2dfddf..c62886d8 100644
--- a/examples/TopsyTurvy/TopsyTurvy.ino
+++ b/examples/TopsyTurvy/TopsyTurvy.ino
@@ -1,6 +1,6 @@
 /* -*- mode: c++ -*-
  * Kaleidoscope-TopsyTurvy -- Turn the effect of Shift upside down for certain keys
- * Copyright (C) 2017  Gergely Nagy
+ * Copyright (C) 2017, 2018  Gergely Nagy
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -19,6 +19,7 @@
 #include <Kaleidoscope.h>
 #include <Kaleidoscope-TopsyTurvy.h>
 
+// *INDENT-OFF*
 const Key keymaps[][ROWS][COLS] PROGMEM = {
   [0] = KEYMAP_STACKED
   (
@@ -38,10 +39,11 @@ const Key keymaps[][ROWS][COLS] PROGMEM = {
     Key_RightShift, Key_RightAlt, Key_Spacebar, Key_RightControl,
     Key_skip),
 };
+// *INDENT-ON*
 
-void setup() {
-  Kaleidoscope.use(&TopsyTurvy);
+KALEIDOSCOPE_INIT_PLUGINS(TopsyTurvy);
 
+void setup() {
   Kaleidoscope.setup();
 }
 
diff --git a/src/Kaleidoscope/TopsyTurvy.cpp b/src/Kaleidoscope/TopsyTurvy.cpp
index fb1db387..dad4976e 100644
--- a/src/Kaleidoscope/TopsyTurvy.cpp
+++ b/src/Kaleidoscope/TopsyTurvy.cpp
@@ -1,6 +1,6 @@
 /* -*- mode: c++ -*-
  * Kaleidoscope-TopsyTurvy -- Turn the effect of Shift upside down for certain keys
- * Copyright (C) 2017  Gergely Nagy
+ * Copyright (C) 2017, 2018  Gergely Nagy
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -26,16 +26,9 @@ namespace kaleidoscope {
 uint8_t TopsyTurvy::mod_state_;
 uint8_t TopsyTurvy::last_pressed_position_;
 
-TopsyTurvy::TopsyTurvy(void) {
-}
-
-void TopsyTurvy::begin(void) {
-  Kaleidoscope.useEventHandlerHook(eventHandlerHook);
-}
-
-Key TopsyTurvy::eventHandlerHook(Key mapped_key, byte row, byte col, uint8_t key_state) {
+EventHandlerResult TopsyTurvy::onKeyswitchEvent(Key &mapped_key, byte row, byte col, uint8_t key_state) {
   if (key_state & TOPSYTURVY)
-    return mapped_key;
+    return EventHandlerResult::OK;
 
   if (mapped_key.raw == Key_LeftShift.raw)
     bitWrite(mod_state_, 0, keyIsPressed(key_state));
@@ -43,21 +36,22 @@ Key TopsyTurvy::eventHandlerHook(Key mapped_key, byte row, byte col, uint8_t key
     bitWrite(mod_state_, 1, keyIsPressed(key_state));
 
   if (!keyIsPressed(key_state) && !keyWasPressed(key_state))
-    return mapped_key;
+    return EventHandlerResult::OK;
 
   if (mapped_key < ranges::TT_FIRST || mapped_key > ranges::TT_LAST)
-    return mapped_key;
+    return EventHandlerResult::OK;
 
   if (keyToggledOn(key_state)) {
     last_pressed_position_ = row * COLS + col;
   } else {
-    if (last_pressed_position_ != row * COLS + col)
-      return Key_NoKey;
+    if (last_pressed_position_ != row * COLS + col) {
+      return EventHandlerResult::EVENT_CONSUMED;
+    }
   }
 
   Key new_key = {.raw = mapped_key.raw - ranges::TT_FIRST};
   if (new_key.raw == Key_NoKey.raw)
-    return mapped_key;
+    return EventHandlerResult::OK;
 
   // invert the shift state
 
@@ -81,8 +75,23 @@ Key TopsyTurvy::eventHandlerHook(Key mapped_key, byte row, byte col, uint8_t key
       hid::pressRawKey(Key_RightShift);
   }
 
+  return EventHandlerResult::EVENT_CONSUMED;
+}
+
+// Legacy V1 API
+
+#if KALEIDOSCOPE_ENABLE_V1_PLUGIN_API
+void TopsyTurvy::begin() {
+  Kaleidoscope.useEventHandlerHook(legacyEventHandler);
+}
+
+Key TopsyTurvy::legacyEventHandler(Key mapped_key, byte row, byte col, uint8_t key_state) {
+  EventHandlerResult r = ::TopsyTurvy.onKeyswitchEvent(mapped_key, row, col, key_state);
+  if (r == EventHandlerResult::OK)
+    return mapped_key;
   return Key_NoKey;
 }
+#endif
 
 }
 
diff --git a/src/Kaleidoscope/TopsyTurvy.h b/src/Kaleidoscope/TopsyTurvy.h
index f97f665c..9402b6cc 100644
--- a/src/Kaleidoscope/TopsyTurvy.h
+++ b/src/Kaleidoscope/TopsyTurvy.h
@@ -1,6 +1,6 @@
 /* -*- mode: c++ -*-
  * Kaleidoscope-TopsyTurvy -- Turn the effect of Shift upside down for certain keys
- * Copyright (C) 2017  Gergely Nagy
+ * Copyright (C) 2017, 2018  Gergely Nagy
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -27,14 +27,19 @@ namespace kaleidoscope {
 
 class TopsyTurvy: public KaleidoscopePlugin {
  public:
-  TopsyTurvy(void);
+  TopsyTurvy(void) {}
+
+  EventHandlerResult onKeyswitchEvent(Key &mapped_key, byte row, byte col, uint8_t key_state);
+
+#if KALEIDOSCOPE_ENABLE_V1_PLUGIN_API
+ protected:
+  void begin();
+  static Key legacyEventHandler(Key mapped_key, byte row, byte col, uint8_t key_state);
+#endif
 
-  void begin(void) final;
  private:
   static uint8_t mod_state_;
   static uint8_t last_pressed_position_;
-
-  static Key eventHandlerHook(Key mapped_key, byte row, byte col, uint8_t key_state);
 };
 
 }