The Legislative Reference Bureau has announced that it has completed scanning the Wisconsin Administrative Code archive back to 1956 (vol 1 of the Administrative Register).
The Code does not appear in it’s entirety for these archived editions. Rather, each year contains a list of the Administrative Code Registers for each month. The chapters that were inserted or removed that month are linked.
The easiest way to track the history of the Administrative Code is to go the current version available on the LRB website. Find the chapter and section that you need.
Each section includes a History note at the bottom. This will include a citation for the Administrative Register(s) which created and changed the section. Links to the archived Code chapter pages are available here. Follow each of these links to view the chapter as it existed when that change was made. I find that it is best to work in reverse chronological order.
The Code archive is also keyword searchable. This is particularly useful for locating text and chapters that may no longer exist in the current version of the Code.
Some even older versions of the building codes are available via Hathi Trust. The LRB may link those up at some time in the future.