Status as of Octave version 2.0.16/2.1.31

Interface compatibility changes
===============================
contour.m       (reordered parameters)
lin2mu.m        (defaults to -1:1 audio range)
mu2lin.m	(defaults to -1:1 audio range)

Interface compatibility extensions
==================================
__pltopt1__.m   (accepts line types)
axis.m          (accepts command strings 'on', 'off', 'square', etc.)
cross.m		(accepts matrices)
deblank.m	(accepts matrices, better \0 handling)
fftfilt.m	(accepts matrices)
freqz.m		(lots of changes)
image.m	        (accepts x,y)
imagesc.m	(accepts x,y)
polyder.m       (accepts a*b, a/b)
polyderiv.m     (accepts a*b, a/b)
polygcd.m	(new function for auto-reduction on polyder)

Speedups
========
findstr.m
hankel.m
hilb.m
index.m
invhilb.m
kron.m
rindex.m
strrep.m
toeplitz.m
vander.m

2.1 features missing from 2.0
=============================
figure.m        (accepts figure number)
file_in_loadpath.m
is_complex.m
islogical.m
isreal.m
logical.m
