Welcome to the forum.
The Projects will not go away. They should also Open in PrE 8, BUT some things might not translate perfectly. Common wisdom holds to finish all Projects in the version, in which they were started. Still, PrE has always been pretty good at backward compatibility - though NEVER forward compatibility.
Now, once you DO Open your PrE 4 Project in PrE 8, it will be converted. You should get the option to Save_As, with a different file name. This is important, as a PrE 8 Project will NOT Open in PrE 4.
I have to post a contrary opinion.
Opening an old version project in a new version of the program almost always leads to buggy behavior. I very warn against it.
Ah, that "common wisdom."
Yes, there have been issues. Some have had better luck, than others. I'll concede this one to you and to "common wisdom."
You do not mention your computer hardware or OS
So... be aware that there have been messages that v8 requires more computing power than even v7
Thank you for your helpful information. I have one more question: If I install v8, will I still be able to run v4 as usual?
I cannot specifically address PrE 4 and PrE 8, but in very general terms, older versions of almost any of Adobe programs can co-exist with newer versions.
A few things to think about might be file associations, where if you were to Dbl-click on a .PREL file from PrE 4, it would try to open in PrE 8, or vice versa.
Also, there might be duplication of some Functional Content, like many Menu Sets, that appear in both programs.
Probably a few other little things to think about, but in general, this should not be an issue.
Yes you can. Each installation is completely self-contained so there are no problems with having multiple version on the same PC.
Insanity is hereditary, you get it from your children
Thank you very much for your answers. You have been very helpful!
Bill : At this hour, over 20 unwanted messages from Adobe Forum.
I replied to each of them as follows:
«This message not meant for filo4 please do not send again.
filo 4» in the hope this would stop after advising you people several times.
I do not intend to spam.
Please have the webmaster rectify this situation immediately.
The problem isn't with the forum, filo. It's likely a piece of malware on your system.