Wholly greetings!
  QjackCtl 0.5.5 (black-friday'18) is released!
QjackCtl [1] is a(n ageing yet modern, not so 'simple' anymore) Qt [2]
application to control the JACK [3] sound server, for the Linux Audio
[5] infrastructure.
Website:
  
https://qjackctl.sourceforge.io
  http://qjackctl.sourceforge.net
Project page:
  
http://sourceforge.net/projects/qjackctl
Downloads:
  
http://sourceforge.net/projects/qjackctl/files
- source tarball:
  
http://download.sf.net/qjackctl/qjackctl-0.5.5.tar.gz
- source package (openSUSE Tumbleweed):
  
http://download.sf.net/qjackctl/qjackctl-0.5.5-34.rncbc.suse.src.rpm
- binary package (openSUSE Tumbleweed):
  
http://download.sf.net/qjackctl/qjackctl-0.5.5-34.rncbc.suse.x86_64.rpm
- AppImage [7] package:
  
http://download.sf.net/qjackctl/qjackctl-0.5.5-6.x86_64.AppImage
Git repos:
  
https://git.code.sf.net/p/qjackctl/code
  https://github.com/rncbc/qjackctl.git
  https://gitlab.com/rncbc/qjackctl.git
  https://bitbucket.com/rncbc/qjackctl.git
Change-log:
- Old deprecated Qt4 build support is no more.
- Graph port sort options added as View / Sort menu.
- System tray options now subject to current desktop environment
availability.
- Also disable Setup / Misc / Other / Save JACK server configuration to
(.jackdrc) when JACK D-Bus interface is enabled.
- Whether to use server synchronous mode option added to Setup /
Settings / Parameters (only applied when JACK D-BUS interface is enabled).
- Disable some Setup / Settings / Advanced parameters when JACK D-Bus
interface is enabled and vice-versa.
- Attempt to power-cycle JACK D-Bus service on demand;
- Marked as probably useless anyway, old "H/W Monitor" option (-H) is
now being ditched from Setup / Settings  / Advanced tab.
- Graph port/connections highlighting.
License:
  QjackCtl [1] is free, open-source Linux Audio [5] software,
distributed under the terms of the GNU General Public License (GPL)
version 2 or later [6].
See also:
  
http://www.rncbc.org/drupal/node/1953
References:
 [1] QjackCtl - A JACK Audio Connection Kit Qt GUI Interface
     
https://qjackctl.sourceforge.io
     http://qjackctl.sourceforge.net
 [2] Qt framework, C++ class library and tools for
     cross-platform application and UI development
     
http://qt.io/
 [3] JACK Audio Connection Kit
     
http://jackaudio.org
 [4] ALSA, Advanced Linux Sound Architecture
     
http://www.alsa-project.org/
 [5] Linux Audio consortium of libre software for audio-related work
     
http://linuxaudio.org
 [6] GPL - GNU General Public License
     
http://www.gnu.org/copyleft/gpl.html
 [7] AppImage, Linux apps that run anywhere
     
http://appimage.org/
Enjoy && keep having fun!
--
rncbc aka Rui Nuno Capela