Why is lubuntu-artwork not being updated in Trusty?

[N. W.]

Dear Lubuntu Artwork developer(s),

why is lubuntu-artwork not being updated in Trusty?

According to this blog post:

http://lubuntublog.blogspot.de/2014/05/box-046.html

and also according to:

https://launchpad.net/~lubuntu-art/+archive/daily

it has been upgraded from 0.45. But in Trusty it's still at 0.45:

http://packages.ubuntu.com/trusty/lubuntu-artwork

Why is that?

Regards