More than 25 years ago, I wrote a novel for middle grade readers called The Law of Gravity. It tells the story of an 11-year-old girl who attempts to make her reclusive, agoraphobic mother come downstairs and out into the world. The sales staff at Morrow Junior Books worried that children would think it was a work of nonfiction. They thought to have a line under the title that called it a novel. I asked my 10-year-old son if he knew what that meant. “Sure,” he answered. “Sometimes it’s fiction, and sometimes it’s nonfiction.” I phoned my editor: “Definitely don’t identify my book as a novel,” I said, telling her about my son. That’s why on the book jacket it said “a story.”

That novel had a good life. The Law of Gravity was well reviewed, was on many state reading lists, and became a Weekly Reader Book Club selection and a Scholastic paperback. Scholastic immediately changed the title to What Goes Up Must Come Down, a very clever title that neither the Morrow staff nor I had considered. The book sold for more than 20 years before it went out of print.

But then a new option became available. StarWalkKids Media is bringing out my book in an e-format. “Would you tweak the story and bring it up to date?” I was asked. Up to date? I thought I had written a contemporary story. But I was wrong.

Upon rereading it, I discovered that a quarter of a century ago is ancient history. My protagonist, Margot Green, lives in New York City. I gave her a large dog so she could safely walk the city streets alone. Nowadays, Margot can carry a cell phone and let her mother know exactly where she is and when she will be home. She can call the police if necessary. Other new devices enable my characters to view movies streamed onto their television sets or other devices.

Thinking back on the books I most loved and read as a youngster, I realize that most were out of date even when I read them. Laura Ingalls Wilder’s Little House Books, for example, were set in the 1870s: Betsy-Tacy and Heidi lived without electricity and without the inventions that came later. The differences in the lives of these characters to my own just seemed to add a charm to the books. I never objected to their old-fashioned settings.

In my book, Margot frequently goes to her local public library accompanied by her dog. When I wrote my book, this was permissible. Nowadays, except for service dogs, animals are not allowed inside the New York Public Library. It would have been an easy thing to eliminate the presence of the dog, except for the charming illustrations by Ingrid Fetz, which show the dog inside the library.

I could eliminate the drawings, but I decided against it, since outside of N.Y.C., children don’t know the library’s ruling about animals. Another drawing that is a problem shows Margot riding a bike without a helmet. Hopefully this won’t upset my e-readers.

The value of money is always a problem with passing time. I increased the amount Margot was paid for babysitting to $10 an hour. Shea Stadium, where the New York Mets played baseball, has been replaced by Citifield. Luckily, I never mentioned the price of the tickets when Margot went to see a baseball game.

I also made some language changes in my revision. Originally, Margot sits “Indian style,” but nowadays this is a politically incorrect usage. So in the updated version, Margot is sitting cross-legged.

At the conclusion of most chapters, Margot sends a letter to her best friend, one of those old-fashioned letters that are placed in an envelope, sealed, and mailed with a postage stamp attached. Today, paper letters are passé. The appropriate thing for Margot to do in this day and age is to send a text message. The revised edition of my book has text messages. They were not written by me. My 15-year-old granddaughter, Juliet Hurwitz, took on the assignment!

The e-book will be available with the title What Goes Up Must Come Down. It will also say, “Original Title: The Law of Gravity.” And hopefully, the story will live happily ever after—at least until another wave of new technology arrives on the scene.

Johanna Hurwitz is the author of 75 books for young readers; many are now available exclusively as e-books.