Copies on the NeoLemmix website have been updated, as have the auto-downloadable copies.
If you use auto-download and want to make sure you have the latest versions, delete these graphic sets from your "styles" folder (the next time you try to play a level that uses them, unless it's in an NXP that also includes copies of the styles, it will redownload them again), as NeoLemmix currently does not check if a newer version is available of a style (it only downloads if you don't have the style at all):
beach.dat
castle.dat
cavelem.dat
circus.dat
city.dat
egyptian.dat
highland.dat
l3_biolab.dat
medieval.dat
outdoor.dat
polar.dat
shadow.dat
space.dat
sports.dat
(note that "epic.dat" is NOT among the auto-downloadable ones, so do not delete it, you'll need to replace this one manually (the reason is that I want to discourage use of "multi-styles-in-one" graphic sets like that one, given that mixing graphic sets will be possible in the future and these kind of graphic sets will make switching over to such a system messier))