What is the difference between Concatenate() and concatenate() layers in Keras / TensorFlow 2.0?
Keras provides 2 kinds of API i.e. Sequential and Functional. And because of this 2 kind of API, the difference is there in them.


Concatenate is used when you are using Sequential API
concatenate is used when you are using Functional API


Just look into the following documentation:
https://keras.io/layers/merge/