Archives For November 30, 1999

PHP finally released 8.2.0 release after 7 release candidates. Here are the new features and how to install guide for all current Ubuntu LTS.

PHP 8.2.0 allows to mark a class as readonly, which will add the readonly modifier to every declared property, and prevent the creation of dynamic properties. Moreover, using the AllowDynamicProperties attribute on readonly class will trigger a compile-time error.

Other release highlights in PHP 8.2.0 include:

  • Disjunctive Normal Form (DNF) Types
  • New stand-alone types: null, false, and true
  • New “Random” extension
  • Constants in traits
  • Deprecate dynamic properties

There are as well numerous bug-fixes and other changes in the release. See the changelog for details.

How to Install Php 8.2 in Ubuntu:

Not recommended for beginners. Only install PHP 8.2 for web developing purpose or there’s specific feature or bug-fix you need in this release.

The popular Ondřej Surý’s PPA has built the package for all current Ubuntu LTS: Ubuntu 18.04, Ubuntu 20.04 and Ubuntu 22.04.

1. First, open terminal or connect to your Ubuntu server and run command to add the PPA:

LC_ALL=C.UTF-8 sudo add-apt-repository ppa:ondrej/php

Run sudo apt install software-properties-common in case the command does not exist. And, type user password (no asterisk feedback) when it asks and hit Enter to continue.

2. Then, install Php packages accordingly. For example, install apache2 module and mysql module via command:

sudo apt install php8.2 libapache2-mod-php8.2 php8.2-mysql

Or install the FPM-CGI binary for use with Nginx:

sudo apt install php8.2 php8.2-fpm php8.2-mysql

For Ubuntu 18.04, run sudo apt update first to refresh package cache.

After installed it, remember to configure your http server (apache 2 or nginx) for the new PHP package, and configure php8.2 via files under ‘/etc/php/8.2/’.

Uninstall Php 8.2

To remove the package, simply run command:

sudo apt remove --autoremove php8.2 libapache2-mod-php8.2 php8.2-*

And remove the Ubuntu PPA via command:

sudo add-apt-repository --remove ppa:ondrej/php

Want to change system power mode between Performance, Balanced, and Power Saver automatically when plug / un-plug power supply?

Here’s an extension can do the job for Ubuntu 22.04, Ubuntu 24.04, Fedora 38/39, Debian 12, Arch and other Linux with GNOME from version 42 to 46.

GNOME introduced setting options to switch power mode since v40. For laptop running on AC power supply, user may use ‘Performance’ mode for gaming or doing heavy work. To prevent from draining power fast after un-plug AC power, it’s better to switch to ‘Balanced’ mode, or even ‘Power Saver’ mode when battery level is low. To automate this work, ‘Power Profile Switcher’ extension was born.
Continue Reading…

Unlike Windows, Ubuntu so far does not have real-time GPU usage info displayed in its system monitor application. If you want to check how much your graphic card is in use, then this simple tutorial may help!

Method 1: Use Mission Center (Graphical App)

A graphical app is always good choice for beginners. And, Mission Center is the one that provides a Windows Task Manager look like interface for monitoring system resource usage.

It supports monitoring overall GPU usage, video encoder and decoder usage, memory usage and power consumption. With the power of nvtop, it supports AMD, Apple, Huawei, Intel, NVIDIA and Qualcomm GPUs.

To install Mission Center, press Ctrl+Alt+T on keyboard to open up a terminal window. Then, run the commands below one by one to install the Flatpak package.

  • First, run command to enable Flatpak support:
    sudo apt install flatpak

  • Then, install Mission Center flatpak package via command:
    flatpak install https://dl.flathub.org/repo/appstream/io.missioncenter.MissionCenter.flatpakref

If this is the first app installed as Flatpak package, you may need to log out and back in to make app icon visible in start menu (or Gnome app grid).

(Optional) To uninstall Mission Center, open terminal and run command:

flatpak uninstall --delete-data io.missioncenter.MissionCenter

Also run flatpak uninstall --unused to clear useless runtime libraries.

Method 2: Monitor GPU usage from Command Line

For Ubuntu server and those who prefer to the job from command line, there are few tools can do the job. They include intel-gpu-tools for Intel GPU, and nvtop for Intel, AMD, and NVIDIA.

Check Intel GPU usage in Ubuntu:

For the integrated Intel graphics card, there’s a command line tool intel_gpu_top can do the job.

1. First, press Ctrl+Alt+T on terminal to open a terminal window. When it opens, run command to install the package:

sudo apt install intel-gpu-tools

Type user password when it asks (no asterisk feedback) and hit Enter.

2. Then, run command to start it:

sudo intel_gpu_top

As you can see, it shows real-time IMC read and write speed, power usage, as well as percentage usage of 3D/Render, Blitter, Video, and VideoEnhance.

Monitor AMD/NVIDIA GPU usage in Ubuntu

For NVIDIA and AMD graphics card, there’s a htop like task monitor called nvtop (Neat Videocard TOP).

It shows real-time GPU and GPU Memory usage in both total and per process basis, along with temperature, power usage, and graph information.

nvtop, image from https://github.com/Syllo/nvtop

nvtop also supports Intel GPU, however, it does not work in my case with i5-4590 (HD4600), and i3-6006U (HD 520).

Install nvtop in Ubuntu:

The tool is available in Ubuntu system repository, but old for Ubuntu 22.04 and Ubuntu 20.04. For the latest version, it has an official PPA contains the most recent package.

1. First, press Ctrl+Alt+T on keyboard to open terminal. Then, run command to add the PPA:

sudo add-apt-repository ppa:flexiondotorg/nvtop

For Ubuntu 24.04, skip the PPA, just the command below to install. Type user password (no asterisk feedback) when it asks and hit Enter to continue.

2. Then, run command to install the tool:

sudo apt install nvtop

For Linux Mint, run sudo apt update first to refresh package cache.

Finally, either search for and launch it from ‘Activities’ overview (or start menu), or run nvtop command to start monitoring your GPU.

(Optional) Remove nvtop

To remove the PPA repository, open terminal and run command:

sudo add-apt-repository --remove ppa:flexiondotorg/nvtop

And remove nvtop if you want via command:

sudo apt remove nvtop

The free open-source Inkscape vector graphics editor got a new maintenance release for the 1.2 series.

The is the second update for Inkscape 1.2, which finally makes OpenClipart import available for Windows and Linux user using AppImage. And, Color extensions works on patterns again.

For macOS, spellchecking finally works and undo/redo options are back in the menu. For Linux, the snap package is no longer possible to install with --classic option. Meaning the snap won’t be able to access data outside of user’s home directory.

Other changes in Inkscape 1.2.2 include:

  • no longer freezes when rotating objects with snapping activated under certain conditions
  • Dithering now disabled by default due to performance loss.
  • Several fixes to the DXF14 export
  • TIFF export now supports transparency
  • DPI attribute is preserved for JPG and TIFF raster export
  • Correct PNG file permission in Linux.
  • Measure tool now indicates correct positions and sizes for shapes

There are as well various other bug-fixes and improvements, see the release note for details.

How to Install Inkscape 1.2.2 in Ubuntu & other Linux

Inkscape website offers official Windows, macOS, Linux, and source tarball, available to download at the link below:

For Linux, it’s available to install via AppImage, Snap, and deb (through PPA), and Flatpak.

Option 1: Snap

Snap is an universal package that runs in sandbox. Ubuntu 20.04 and higher can simply search for and install Inkscape as Snap from Ubuntu Software:

Install inkscape as Snap from Ubuntu Software

Option 2: AppImage

AppImage is a portable package works in most Linux. No installation required, just grab the package (via link above), enable ‘Allow executing file as program‘ in file Properties dialog. Finally, click Run the package to launch the editor.

Option 3: Ubuntu PPA

For the native .deb package, it has an official stable PPA contains the latest package for Ubuntu 20.04, Ubuntu 22.04, and Ubuntu 22.10.  Not only for modern 64-bit OS, the PPA now also supports for arm64/armhf architecture types.

1. First, press Ctrl+Alt+T on keyboard to open terminal. When it opens, run command to add the PPA:

sudo add-apt-repository ppa:inkscape.dev/stable

Type user password (no asterisk feedback) when it asks and hit Enter to continue.

2. Then either install the image editor as native .deb package via:

sudo apt install inkscape

NOTE: Linux Mint user need to refresh package cache via sudo apt update first.

Or use ‘Software Updater’ to upgrade from an old version:

Option 4: Flatpak

Flatpak is another universal package format that runs in sandbox. Different to previous package formats, Inkscape as Flatpak is maintained by the open-source community.

Ubuntu 20.04 and higher and follow the steps below to install Inkscape as Flatpak package:

  • 1. First, open terminal and install Flatpak daemon via command:
    sudo apt install flatpak
  • 2. Then install Inkscape as Flatpak using command:
    flatpak install https://dl.flathub.org/repo/appstream/org.inkscape.Inkscape.flatpakref

Uninstall Inkscape:

Depends on which package you installed, choose from the methods below:

  • For Snap package, remove it from Ubuntu Software.
  • For AppImage, just remove the package file.
  • To remove the Inkscape PPA, open terminal and run command:
    sudo add-apt-repository --remove ppa:inkscape.dev/stable

    Also remove the editor if you want via command:

    sudo apt remove --autoremove inkscape
  • For the Flatpak package, use command:
    flatpak uninstall --delete-data org.inkscape.Inkscape

    And run flatpak uninstall –unused to remove useless runtime libraries.

This simple tutorial shows how to fix the launching issue for TypeCatcher in Ubuntu 22.04 or other Linux with Python 3.9 & higher.

TypeCatcher is a simple GTK application to download and install Google webfonts for off-line use. The app is available to install in Ubuntu Software for all current Ubuntu releases. However, it does not launch in Ubuntu since 21.10.

TypeCatcher, download & install Google Fonts

When trying to launch it from command line, it outputs something like this:

Traceback (most recent call last):
File “/usr/lib/python3/dist-packages/typecatcher_lib/Application.py”, line 30, in on_activate
self.window = TypeCatcherWindow.TypeCatcherWindow()
File “/usr/lib/python3/dist-packages/typecatcher_lib/Window.py”, line 47, in __new__
builder = get_builder(‘TypeCatcherWindow’)
File “/usr/lib/python3/dist-packages/typecatcher_lib/helpers.py”, line 44, in get_builder
builder.add_from_file(ui_filename)
File “/usr/lib/python3/dist-packages/typecatcher_lib/Builder.py”, line 86, in add_from_file
ele_widgets = tree.getiterator(“object”)
AttributeError: ‘ElementTree’ object has no attribute ‘getiterator’

The issue is because of the removal of getiterator() methods from xml.etree.ElementTree module in Python 3.9, which was deprecated since Python 3.2.

As the announcement indicates, simply use iter() method instead will fix the issue.

Methods getchildren() and getiterator() of classes ElementTree and Element in the ElementTree module have been removed. They were deprecated in Python 3.2. Use iter(x) or list(x) instead of x.getchildren() and x.iter() or list(x.iter()) instead of x.getiterator().

1. First, search for and open a terminal window from either start menu or ‘Activities’ overview depends on your desktop environment.

2. When terminal opens, run command to edit the file that contains the ‘getiterator()’ method (see the first screenshot). In the case, it’s “/usr/lib/python3/dist-packages/typecatcher_lib/Builder.py”.

sudo gedit /usr/lib/python3/dist-packages/typecatcher_lib/Builder.py

replace gedit to your favorite text editor, or use nano command line editor that works in most Linux.

3. When files opens, find out and replace tree.getiterator with tree.iter.

For Gedit text editor, just go to menu, click open ‘Find and Replace’ dialog. Finally, insert tree.getiterator as ‘Find’, and ‘tree.iter‘ as ‘Replace with’, then click on ‘Replace All’ button.

For nano text editor, press Alt+R when the file opens in terminal window. Then type tree.getiterator when it indicates ‘Search (to replace)’, hit Enter, and insert tree.iter when prompts ‘Replace with’. Finally, hit Enter and type y. Or, just use arrow keys to find and replace the keyword (there are 2) manually. And, press Ctrl+x, type y, and hit Enter to save changes.

After saving the file, try to launch it either from ‘Activities’ overview or command line, and enjoy!

PyCharm Python IDE 2022.3 was finally released a few days ago. Here are the new features and how to guide for installing it in Ubuntu Linux.

Changes in PyCharm 2022.3 include:

  • Ability to search, install, and delete Conda packages through the Python Packages tool window
  • New Settings Sync plugin
  • export DataFrames in various formats (for professional only)
  • The Quick Documentation popup now displays the Attributes section of the class docstrings
  • Support await keyword in the built-in Python Console.
  • Experimental asyncio support for the debugger.
  • Vitest support (for professional only)
  • New project templates for Next.js and Vite (for professional only)
  • Redis support (for professional only)

How to Install PyCharm 2022.3 in Ubuntu Linux

There are 3 ways to install the Python IDE in Ubuntu and other Linux: Snap, Flatpak, and portable tarball. Just choose the one that you prefer.

Option 1: PyCharm Snap package

The easiest way to get the IDE is using the official Snap package. It is a containerized software package that run in sandbox, and updates automatically.

For Ubuntu 20.04, Ubuntu 22.04 and higher, simply search for ‘PyCharm’ then install either community or professional edition from Ubuntu Software.

Or, run command in terminal to install the Snap package:

sudo snap install pycharm-community --classic

Replace pycharm-community with pycharm-professional for the professional edition.

Option 2: PyCharm Portable package (tar.gz)

The website also provides official tar.gz package for downloading at the link below:

Then open the folder that stores the tarball (usually Downloads folder), right-click on blank area and select ‘Open in Terminal‘.

When terminal opens, run the commands below one by one to install it for all system users (replace community with professional accordingly):

  • First, create a folder under ‘/opt’ to store the source:
    sudo mkdir -p /opt/pycharm-community
  • Then extract the tarball into that folder:
    sudo tar -zxf pycharm-community-2022.3.tar.gz --strip-components=1 -C /opt/pycharm-community/
  • Finally, create & edit shortcut icon file for the IDE package:
    sudo gedit /usr/share/applications/pycharm-community.desktop

    Replace gedit with nano for Ubuntu 22.10.

The last command should open an empty text editor window. There paste the lines below and save it.

[Desktop Entry]
Name=PyCharm Community Edition
Comment=Lightweight IDE for Python & Scientific development
Exec=/opt/pycharm-community/bin/pycharm.sh
Icon=/opt/pycharm-community/bin/pycharm.svg
Terminal=false
Type=Application
Categories=Development;IDE;
StartupWMClass=jetbrains-pycharm

After saving the file, you should be able to search for and launch PyCharm IDE from start menu or ‘Activities’ overview, depends on your desktop environment.

Option 3: PyCharm Flatpak

The open-source community also maintains the PyCharm packages as Flatpak package, which is also containerized package runs in sandbox.

First, open terminal by pressing Ctrl+Alt+T keys on keyboard. When it opens, run command to install the daemon package:

sudo apt install flatpak

Next, run command to install PyCharm Community as Flatpak:

flatpak install https://dl.flathub.org/repo/appstream/com.jetbrains.PyCharm-Community.flatpakref

Or, install the professional version as Flatpak via command:

flatpak install https://dl.flathub.org/repo/appstream/com.jetbrains.PyCharm-Professional.flatpakref

Uninstall PyCharm

For the Snap package, remove it either via Ubuntu Software or by running command in terminal:

sudo snap remove pycharm-community --classic

For the portable package, remove the source as well as shortcut file via command:

sudo rm -R /opt/pycharm-community
sudo rm /usr/share/applications/pycharm-community.desktop

And, remove the Flatpak package via command:

flatpak uninstall --delete-data com.jetbrains.PyCharm-Community

For the professional edition, remove pycharm-community in the commands above with pycharm-professional.

Remember Midori? The lightweight web browser that was default in Elementary OS and Bodhi Linux revived!

Midori was a popular lightweight web browser used the WebKitGTK rendering engine and GTK UI toolkit. The development of the project was however discontinued more than 3 years ago. And, Ubuntu even removed it from system repository since Ubuntu 22.04 LTS.

According to the Wikipedia, the Midori project has been merged with the Astian Foundation in 2019. And, Astian announced a week ago that Midori browser is still alive!

It’s now Chromium based web browser that using Electron and React with both desktop edition for Linux, macOS, and Windows, and mobile edition for Android.

The browser still aims to be lightweight, fast and free. It’s still an open-source app, with the source code host in gitlab project page. (update: the project page does no longer exist! If you know where Astian hosts the source code, please leave comment below.)

Midori web browser next generation

The new Midori browser so far features:

  • New logo.
  • Adblock integration, block ads out-of-the-box.
  • Incognito mode support.
  • Chromium based, without Google services and low resources usage
  • Fast and highly customizable UI.
  • Partial Chrome extensions support.
  • To use its own open-source AstianGO search engine. Though, it so far uses DuckDuckGo as default. While Google, Bing, and Ecosia available for choice.

How to Install New Midori web browser in Ubuntu & other Linux

Astian offers official Midori packages for Linux through AppImage and .deb package.

Option 1: AppImage

AppImage is a portable package format without installation required. Just select download it from its website:

Then, right-click on AppImage in file manager. Open ‘Properties’ dialog and grant ‘execute as program’ permission. Finally, click run the package to launch the web browser.

Option 2: Deb package

It also provides official .deb packages for modern 64-bit computers, available to download via the link button below:

NOTE: The Debian (.deb) package seems broken at the moment of writing. It won’t install in my case in Ubuntu 22.04, Debian 11 either via double-clicking or using apt install command. So please try AppImage until Astian fixed the issue.

This tutorial shows how to install the latest version of RawTherapee (5.11 so far) in all current Ubuntu releases!

RawTherapee, the free open-source raw image converter and digital photo processor, released version 5.11 recently on August 25. See

RawTherapee 5.9 features new “Spot Removing Tool” under Details tab for removing dust specks and small objects; Local Adjustments tool under Local tab for performing a wide range of operations on an area of the image determined by its geometry or color; Preprocess White Balance tool under Raw tab to specify whether channels should be balanced automatically or whether the white balance values recorded by the camera should be used instead; and a new Perspective Correction tool which includes an automated perspective correction feature.

Other changes include:

  • include CAM16 in Color Appearance & Lighting tool
  • new automatic white balance method “temperature correlation” for White Balance tool.
  • new waveform, vectorscope and RGB parade modes for the Main Histogram.
  • new dual-demosaicing methods in the Demosaicing tool
  • add saturation adjuster for Haze Removal tool

RawTherapee 5.9

There are as well many new and improved Cameras support, including Canon EOS 100D / Rebel SL1 / Kiss X7, Canon EOS 2000D / Rebel T7 / Kiss X90, Nikon D6, Nikon Z 6II, Nikon Z 7II, and more. See the release note for details.

How to Install RawTherapee (5.11 Updated):

Option 1: AppImage

The software provides official Linux package via AppImage, which is available for downloading at the link below:

Once you got the package, right-click on it to open file ‘Properties’ dialog and add ‘executable as program’ permission. Finally, click the file to launch the photography processor.

NOTE: Ubuntu 22.04+ does not support AppImage out-of-the-box. In case it doesn’t work for you, press Ctrl+Alt+T on keyboard to open terminal and run command sudo apt install libfuse2 to enable it.

Option 2: Flatpak

RawTherapee is also available as Flatpak package that runs in sandbox environment. The package works in most Linux on amd64 and arm64 CPU platforms.

1. First, open terminal (Ctrl+Alt+T) and make sure the daemon package is installed by running command in Ubuntu 20.04, Ubuntu 22.04 and higher:

sudo apt install flatpak

Ubuntu 18.04 and Ubuntu 16.04 user can get the package from this PPA.

2. Then, install Rawtherapee as Flatpak by running command:

flatpak install https://dl.flathub.org/repo/appstream/com.rawtherapee.RawTherapee.flatpakref

Like normal package, you can search for and launch the flatpak app from either ‘Activities’ overview or system start menu depends on desktop environment.


Option 3: Ubuntu PPA

For those who prefer the native .deb packages, there’s also an unofficial PPA contains the packages for Ubuntu 22.04, and Ubuntu 24.04. Also, the package support amd64, arm64 and armhf CPU architecture types.

NOTE: due to outdated system library, librsvg-2.0 in the case, the Ubuntu 20.04 build is stuck at version 5.10.

1. First, press Ctrl+Alt+T on keyboard to open terminal. When it opens, run command to add the PPA:

sudo add-apt-repository ppa:ubuntuhandbook1/rawtherapee

2. Linux Mint users need to manually refresh system package cache after adding PPA, though it’s done automatically in Ubuntu now.

sudo apt update

3. Finally, install the RAW developer software by running command:

sudo apt install rawtherapee

Uninstall RawTherapee

Depends on which package you installed, open terminal (Ctrl+Alt+T) and run command to uninstall the Flatpak:

flatpak uninstall --delete-data com.rawtherapee.RawTherapee

Also run flatpak uninstall --unused to clear useless runtime libraries.

For the .deb package, remove it by running command:

sudo apt remove --autoremove rawtherapee rawtherapee-data

Also remove PPA, either by removing source line via “Software & Updates” tool under Other Software tab, or by running command in terminal:

sudo add-apt-repository --remove ppa:ubuntuhandbook1/rawtherapee

And, for the AppImage, just delete the file in your folder.

Want to measure your application launch time in Linux? There’s an extension can do the job for GNOME desktop.

Meaning Ubuntu, Fedora workstation, and other Linux with GNOME desktop can easily tell how much time it takes for launching an application, which is useful for benchmark and/or software developing purpose.

With the extension enabled, every time you launching an application, an on-screen display pops up shows the loading time in millisecond. Not only for native .deb/.rpm, but also for Snap and Flatpak applications.

How to Install the App Start Time Measure extension

For Ubuntu 22.04, first search for and install “Extension Manager” from Ubuntu Software.

Install Extension Manager in Ubuntu 22.04+

Then launch “Extension Manager” and use it to search & install ‘application start time measure’:

For Ubuntu 20.04, first press Ctrl+Alt+T on keyboard to open terminal. When it opens, run command to install the agent package:

sudo apt install chrome-gnome-shell

Then, go to extension page in the link below and use ON/OFF switch to install it:

Install the browser extension if prompted via link in that page and refresh if you don’t see the ON/OFF switch.

After installing the extension, it should be enable automatically (verify via ‘Gnome Extensions’ or ‘Extension Manager’). You can then launch something and see the magic!

qBittorrent got a new major release this weekend. Here’s the new features and how to install guide for Ubuntu 22.04

qBittorrent 4.5.0 features new icon theme, new color theme, better startup time, and export torrent support. And, it now uses libtorrent 2.0.x in the default binary packages.

Other changes include:

  • Add ‘View’ menu option to show/hide filter sidebar.
  • Add Auto resize columns functionality
  • Allow to use Category paths in Manual mode
  • Allow to disable Automatic mode when default “temp” path changed
  • Add right click menu for status filters
  • Allow setting the number of maximum active checking torrents
  • Allow to set working set limit on non-Windows OS
  • Allow to use POSIX-compliant disk IO type
  • Add Filter files field in new torrent dialog
  • Add file name filter/blacklist
  • Add support for custom SMTP ports
  • Add ability to run external program on torrent added
  • Add infohash and download path columns
  • Allow to set torrent stop condition
  • Add a Moving status filter
  • Add a Use proxy for hostname lookup option
  • Introduce a change listen port cmd option
  • Implement Peer ID Client column for Peers tab
  • Add port forwarding option for embedded tracker

As well, there are various bug-fixes in the release. See more in the news page.

How to install qBittorrent 4.5.0 in Ubuntu 22.04

UPDATE: Due to requirement of Qt6 >= 6.5.0, the PPA will no longer update for Ubuntu 24.04, 22.04, and 20.04. For newer releases, see this tutorial for other installation methods.

The software has an official Ubuntu PPA which however updates the latest package so far only for Ubuntu 22.04, Ubuntu 23.10, Linux Mint 21 and their based systems.

1. First, press Ctrl+Alt+T on keyboard to open a terminal window. When it opens, run command to add the PPA:

sudo add-apt-repository ppa:qbittorrent-team/qbittorrent-stable

Type user password when it asks (no asterisk feedback) and hit Enter to continue.

2. Then, either run software updater (Update Manager) to update the bittorrent client if an old version was installed.

Or install it using command:

sudo apt install qbittorrent

For Linux Mint, either use Software Manager after refreshing package cache, or run sudo apt update before running the command above.

Uninstall/Restore:

Option 1: If you want to downgrade qBittorrent package to stock version in system repository, install ppa-purge tool and purge the PPA by running command in terminal:

sudo apt install ppa-purge && sudo ppa-purge ppa:qbittorrent-team/qbittorrent-stable

Option 2: Or, remove the client package either via Ubuntu Software or by running command:

sudo apt remove --autoremove qbittorrent

And, remove the PPA either via ‘Software & Updates‘ utility under ‘Other Software’ tab or by running command:

sudo add-apt-repository --remove ppa:qbittorrent-team/qbittorrent-stable