convert h5 to onnx: op ReverseV2 is not supported

[jian-yu]

i want to convert keras to onnx from crnn_30.h5, but it show like this:

...
Tensorflow op [crnn/bidirectional/backward_lstm/PartitionedCall/ReverseV2: ReverseV2] is not supported
Tensorflow op [crnn/bidirectional/ReverseV2: ReverseV2] is not supported
Tensorflow op [crnn/bidirectional_1/backward_lstm_1/PartitionedCall/ReverseV2: ReverseV2] is not supported
Tensorflow op [crnn/bidirectional_1/ReverseV2: ReverseV2] is not supported
Unsupported ops: Counter({'ReverseV2': 4})

if you know something about it , plz tell me