I always like to have a printed copy of the user manual handy for references purposes, but printing out each issue gets a bit expensive.Is there any possibility that you can add change bars in the margins so it is easy to see what has changed from the last issue?
That is how "formal" documents get updated in the field of my career..
MS Word provides this facility and it is very easy to implement/use.
Word documents can then very easily be converted to PDFs for putting on your website.
With change bars in use it becomes very easy to quickly see what has been changed.
Thanks
Tony