FAQ: Saving Version 4 Compatible Documents
Can a document created in version 5 be opened in version 4?
By default, documents saved in version 5 can only be reopened by version 5. However, you can create a version 4-compatible Sketchpad document from a version 5 one. With the document open in version 5, choose File | Save As and ask to save the document as "GSP4 Document (Compatibility Version)." If your document takes advantage of features and functionalities available only in version 5, those parts of the document will not be exported to version 4. (You'll receive a warning if this is the case.) In either event, the resulting document can then be opened in version 4.