Upgrade very old version to recent one

[eluser]Unknown[/eluser]
Hello,

One of our customers is still using CodeIgniter v1.0.
Is there an upgrade path from this old one to a recent one?
I've seen the pages with the upgrades, but I don't think this is a good way, especially because the versions between are'nt available anymore.

Thanks,
Tim

[eluser]jairoh_[/eluser]
do it at your own risk sir. but just keep a backup.