Keeping track of your and your collaborators work it is one of the challenges in the research world.
Labguru helps you with it, saving a copy of your team work while working on experiments, protocols or documents, every time you click on 'save'.
The "version history" is available at the bottom of any Labguru page:

It is also accessible from the 'More' menu, at the top of the page, :

The previous versions, available in PDF format, appear in a list ordered by date with the option to sort versions by team members or by date: