Flex/Bison: which version to use?

[Frans Englich]

Hello,

From a vague memory of fellow developers' experiences, I have the idea that 
what version of Bison/Flex one use is significant. But perhaps that isn't 
relevant anymore.

For my project, written in C++, I simply downloaded the latest versions(at 
least at that time); I use Bison 2.0, and Flex 2.5.31.

Does it matter what version one uses? What is recommended? For what scenarios 
does version matter(portability, programming language, functionality, etc)? 
(if at all)

Another question; I noticed that I had "flex++" installed, as well as that 
"bison++" exists, after a quick googling. Are those "++" versions established 
software which people use? What are their advantages? When should I need to 
think about whether I should use the "++" programs?


Thanks in advance,

                Frans