When we first moved the documentation to the DocOps wiki platform, we had a system for generating PDFs on the fly based on the context of what you were viewing. This system turned out not to scale well. We replaced it some months ago with cached PDFs and EPUBs. Each PDF or EPUB includes the entire documentation set for that product. The PDFs and EPUBs are regenerated when the documentation is republished.
These PDFs have a date stamp on the front, showing when they were generated. On the home page of the wiki, there is a set of announcements at the top. Whenever the wiki is republished (and the PDF is regenerated), the writer adds a new announcement, with a date stamp, identifying the PTFs and everything else significant that went into the republishing. This information is also in the Release Notes of the documentation, including the PDF. The value of the announcement is that you can use the Watch function on the homepage and receive notification when the homepage, *and only the homepage*, is changed. Thus you will receive notification of every announcement, which will let you know when you need to download a new copy of the PDF and why.
We hope to work out a more automated solution.