And, to make it even more "simpler" the server is the network's file server, gives access to the Internet and also has the main application made for the enterprise and it's databases, from which I know nothing about how they are design and built, etc.
But, thankfully, it went very smooth and the only problem I had was with program I had installed previously (a file manager) that after the upgrade wasn't working. So I had to remove it, remove a library it depended on and re-install the library and then the file manager again.
I had also a few minor adjustments to do after the upgrade but nothing complicated.
I think that the best "reward" we could have had was the owner of the enterprise asking us if we had already done the upgrade as he hadn't noticed the down time of the server....
Why can't it always be like this? :-)))