Our filters will all install and run on both ISA 2004 and 2006.
Some of the older filters may no longer be required due to new functionality that has been added to the core ISA product. But you can still use them if there is a feature you need, or you prefer the filter's solution.
One caveat to note is that holders of our old "Lite" version licenses will need to upgrade to the new standard license if they wish to use their filter on ISA 2006. Contact us if you need to upgrade, and we can provide a discount from the retail license cost.