Downgrade to fastai 0.7

For some reasons I am trying to install fastai 0.7 using google colab environment. But, I face many dependency incompatibility problems.
I tried to solve some of them
but there is still some errors in importing fastai.transforms:

ImportError: cannot import name ‘PILLOW_VERSION’

to run: fastai/fastai1/courses/dl1/lesson1.ipynb

Any idea?