This has happened to me twice in the last month, so here is a free solution.
I’m trying to get a newer Illustrator EPS file to open in my CS3 Version.
- Start Adobe Illustrator CS3.
- File – New.
- Select – Drag and Drop your newer Illustrator EPS file into Illustrator.
- Now you can do a Save As and save your file in your older Illustrator version.
Here’s a YouTube video with the solution.