From the release note of 5.1
(Apart from the usual tons of updates and bugfixes)
Update to Debian etch/testing as base distribution
Linux Kernel 2.6.19(.1) + fuse 2.6.1
cloop 2.05 Realtime Decompression with extended block-buffering for reduction of CD/DVD access latency
Replacing unionfs by aufs for better stability & performance
ntfs-3g (12.12.2006) for full transparent NTFS write support, also tested with boot options knoppix tohd= and knoppix fromhd=. Please note the hints about ntfs-3g below.
ntfsprogs-Update (ntfsresize, ntfsmount, ntfsfix)
integration of 3D desktop beryl+emerald as add-on for KDE (manual start with gnome is also possible), via boot option knoppix desktop=beryl. Please note the hints given below.
Experimental script for creating a bootable flash-pendrive from a running KNOPPIX live session (mkbootdev by Martin Öhler)