I\'m using Keras 1.0. My problem is identical to this one (How to implement a Mean Pooling layer in Keras), but the answer there does not seem to be sufficient for me.
I just attempted to implement the same model as the original poster, and I'm using Keras 2.0.3. The mean pooling after LSTM worked when I used GlobalAveragePooling1D, just make sure return_sequences=True in the LSTM layer. Give it a try!