Update README.md

Author: solivr

README.md

@@ -6,6 +6,8 @@ Implementation of a Convolutional Recurrent Neural Network (CRNN) for image-base
 
 This implementation is based on Tensorflow 2.0 and uses `tf.keras` and `tf.data` modules to build the model and to handle input data.
 
+To access the previous version implementing Shi et al. paper, go to the [v.0.5.2](https://github.com/solivr/tf-crnn/tree/v0.5.2) tag.
+
 
 ## Installation
 `tf_crnn` makes use of `tensorflow-gpu` package (so CUDA and cuDNN are needed). 
@@ -40,4 +42,4 @@ See also the [docs](https://tf-crnn.readthedocs.io/en/latest/start/index.html#)
 
     python training.py with config.json
 
-More details in the [documentation](https://tf-crnn.readthedocs.io/en/latest/start/training.html#example-of-training).
+More details in the [documentation](https://tf-crnn.readthedocs.io/en/latest/start/training.html#example-of-training).