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+# Change Log
+
+## 2013-08-18 - Destroying an entity invalidates all other references
+
+Previously, `Entity::Id` was a simple integer index (slot) into vectors in the `EntityManager`. EntityX also maintains a list of deleted entity slots that are reused when new entities are created. This reduces the size and frequency of vector reallocation. The downside though, was that if a slot was reused, entity IDs referencing the entity before reallocation would be invalidated on reuse.
+
+Each slot now also has a version number and a "valid" bit associated with it. When an entity is allocated the version is incremented and the valid bit set. When an entity is destroyed, the valid bit is cleared. `Entity::Id` now contains all of this information and can correctly determine if an ID is still valid across destroy/create.
+
+## 2013-08-17 - Python scripting, and a more robust build system
+
+Two big changes in this release:
+
+1. Python scripting support (alpha).
+    - Bridges the EntityX entity-component system into Python.
+    - Components and entities can both be defined in Python.
+    - Systems must still be defined in C++, for performance reasons.
+
+    Note that there is one major design difference between the Python ECS model and the C++ model: entities in Python can receive and handle events.
+ 
+    See the [README](https://github.com/alecthomas/entityx/blob/master/entityx/python/README.md) for help, and the [C++](https://github.com/alecthomas/entityx/blob/master/entityx/python/PythonSystem_test.cc) and [Python](https://github.com/alecthomas/entityx/tree/master/entityx/python/entityx/tests) test source for more examples.
+
+2. Made the build system much more robust, including automatic feature selection with manual override.