Does iPad air include a new bluetooth programme which isn´t compatible with my older devices (4 years old) ?
At this time, it limited to other devices running ios 7.x.
mobile Nokia N8
You going to have to install more software on the N8. I suggest you try dropbox. You can look for some protocol that both iPad & the N8 support.
There are lots of ways of moving files.
A simple and popular way to copy files and share files amoung your devices.
Using iTunes to transfer files:
Files Connect -- The swiss army knife of remote file connect
iExplorer -- " iExplorer's disk mounting features allow you to use your iPhone, iPod or iPad like a USB flash drive."
Windows File server
"In education and business users increasingly expect to be able to access their data anytime, anywhere and from any device."
Configure WebDave on your server.
This thread has good info.
How to transfer files from your iPad to your PC with iPad to Computer Transfer
More ways to transfer files and access Word documents: