kde-style-qtcurve-qt4 software package provides QtCurve widget style for applications based on Qt 4.x, you can install in your Ubuntu 16.04 LTS (Xenial Xerus) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install kde-style-qtcurve-qt4
kde-style-qtcurve-qt4 is installed in your system.
Make ensure the kde-style-qtcurve-qt4 package were installed using the commands given below,
$ sudo dpkg-query -l | grep kde-style-qtcurve-qt4 *
You will get with kde-style-qtcurve-qt4 package name, version, architecture and description in a table
| Distro | Ubuntu 16 04 lts xenial xerus |
| Section | KDE |
| Package | kde-style-qtcurve-qt4 |
| Version | 1.8.18+git20160112-0cd6aae-1 |
| Description | QtCurve widget style for applications based on Qt 4.x |
| Sub Section | KDE |