Jube5678 asks:
1. I get a message from time to time "SVG viewer is not installed - Download now?" with OK or Cancel to click on. What does this mean?

2. I have Adobe 6.0 - Message comes up "do you want to upgrade?" Is it necessary?

The Answers:
1. The SVG viewer is a component of Adobe reader that is needed to view Scalable Vector Graphics (hence the SVG). I would assume you are getting this message when you try to view a particular document that does have this content. It is OK to download and install.

2. Jube doesn't mention which form of Adobe 6.0 is in use. I assume we are talking about either the free Adobe reader or the Adobe PDF creator. Version 6.0 of both products works well and as long as you are not having a problem, then I would see no need to update/upgrade. It seems like Adobe is coming out with new updates almost weekly and I only bother to update when a major change is made. Since Jube specifically mentioned UPGRADE, then we may be talking about the PDF Creator. This will probably involve a cost and again, I see no need to upgrade unless you are having problems.

RELATED LINK: Adobe SVG Info.