diff --git a/src/Hooks.cpp b/src/Hooks.cpp
index 842528d8d..3c3478ab3 100644
--- a/src/Hooks.cpp
+++ b/src/Hooks.cpp
@@ -197,8 +197,9 @@ void Hooks::onExit ()
 // - all emitted non-JSON lines are considered feedback messages if the exit
 //   code is zero, otherwise they are considered errors.
 //
-void Hooks::onAdd (Task& after)
+void Hooks::onAdd (std::vector <Task>& changes)
 {
+/*
   context.timer_hooks.start ();
   if (! _enabled)
     return;
@@ -249,6 +250,7 @@ void Hooks::onAdd (Task& after)
   }
 
   context.timer_hooks.stop ();
+*/
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -266,8 +268,9 @@ void Hooks::onAdd (Task& after)
 // - all emitted non-JSON lines are considered feedback messages if the exit
 //   code is zero, otherwise they are considered errors.
 //
-void Hooks::onModify (const Task& before, Task& after)
+void Hooks::onModify (const Task& before, std::vector <Task>& changes)
 {
+/*
   context.timer_hooks.start ();
   if (! _enabled)
     return;
@@ -322,6 +325,7 @@ void Hooks::onModify (const Task& before, Task& after)
   }
 
   context.timer_hooks.stop ();
+*/
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/src/Hooks.h b/src/Hooks.h
index 7e5d1608a..b6e19accc 100644
--- a/src/Hooks.h
+++ b/src/Hooks.h
@@ -29,6 +29,7 @@
 
 #include <vector>
 #include <string>
+#include <Task.h>
 
 class Hooks
 {
@@ -43,8 +44,8 @@ public:
 
   void onLaunch ();
   void onExit ();
-  void onAdd (Task&);
-  void onModify (const Task&, Task&);
+  void onAdd (std::vector <Task>&);
+  void onModify (const Task&, std::vector <Task>&);
 
   std::vector <std::string> list ();
 
diff --git a/src/TDB2.cpp b/src/TDB2.cpp
index 3baf8a2c6..d60ad3bc9 100644
--- a/src/TDB2.cpp
+++ b/src/TDB2.cpp
@@ -570,9 +570,7 @@ void TDB2::add (Task& task, bool add_to_backlog /* = true */)
   // Create a vector tasks, as hooks can cause them to multiply.
   std::vector <Task> changes;
   changes.push_back (task);
-
-  // TODO call hooks.
-  // context.hooks.onAdd (changes);
+  context.hooks.onAdd (changes);
 
   update (uuid, task, add_to_backlog, changes);
 }
@@ -584,12 +582,14 @@ void TDB2::modify (Task& task, bool add_to_backlog /* = true */)
   task.validate (false);
   std::string uuid = task.get ("uuid");
 
+  // Get the unmodified task as reference, so the hook can compare.
+  Task original;
+  get (uuid, original);
+
   // Create a vector tasks, as hooks can cause them to multiply.
   std::vector <Task> changes;
   changes.push_back (task);
-
-  // TODO call hooks.
-  // context.hooks.onModify (changes);
+  context.hooks.onModify (original, changes);
 
   update (uuid, task, add_to_backlog, changes);
 }