Whats the difference

[Mihir Sanghavi]

Hi,

I am a new member to FreeBSD on the whole. I would like to know the
differences between FreeBSD 4.7, 5.X and 6.1. My company is using BSD
4.7 currently and I would like it to change to 5 or 6. What technical
difficulties might I face or how much code would be needed to
re-written. I do understand that these are too broad questions but any
sort of input would be helpful at this stage. Please email me back to
mihir.sanghavi at gmail.com. Thanking everyone in advance.

Regards,

Mihir