Actually, that version is several hundred versions out of date.
What do you mean? Was there an error message? (If so, please post it.) How were you trying to open them, as standalone files or from the Businesses page of the application?
When were the backup files made? If they were made prior to v20.9.89, they will not be converted to the necessary SQLite format currently in use. See this post from the developer: Business database not valid, desktop version on Windows 10 - #2 by lubos.