What is the previous version of HTML prior to HTML5?

Before HTML was before the web, so there are no immediate comparisons.

If we consider HTML as a document format, Microsoft Word (for DOS and Windows), MacWrite (for Mac) and Postscript (for Unix) existed before HTML, and could be used to share documents by sending the files by mail.

If we consider HTML in the sense of "web pages", a place where you can navigate around, read messages and download files, the closest analogy to a web site was the BBS - Bulletin Board System. It was pure text and normally accessed via dial up modems, but would allow you to leave messages, discuss with other users and download photos and software.

See related link for BBS, along with a screenshot.