There is some discussion of the differences in the two editions in https://news.ycombinator.com/item?id=4665466 as well as the reviews on Amazon. I am going to give the updated version a try.
I got the recommendation here in HN and I used the book with my 2 daughters. I started with my first daughter when she was 4.5 years old. I started with my second daughter at an older age because she was showing a slight case of dyslexia. It took 2 years to finish the book with each of them. After they were done they could read everything. My second daughter is 9 and is almost done with Oliver Twist.
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