Hello Linux Geeksters. As you may know, the LXDE developers have started the porting of their LXDE desktop environment to Qt, the new project being called LXQt. While LXDE is based on GTK+2, the developers have decided to port LXDE on Qt5, instead of GTK+3.
Also worth mentioning, due to the fact that LXQt is still under massive development, Lubuntu 14.10 will be still using LXDE. If you want to test LXQt on your Ubuntu 14.04 or Ubuntu 13.10 system, see the instructions in this article.
Due to the fact that Lubuntu 14.04 Trusty Tahr is a LTS version, Canonical forbids the Lubuntu developers to add unstable packages in the official repositories.
So, if you want to get the latest updates on your Lubuntu 14.04 system (including the Qt packages belonging to LXQt), you should add the Lubuntu Staging PPA, update the local repository index and upgrade the system:
$ sudo add-apt-repository ppa:lubuntu-dev/staging
$ sudo apt-get update
$ sudo apt-get dist-upgrade
Among others, the PPA provides a new version of GNumeric, updated artwork an a new version of Sylpheed.