This week we did a little bit of everything, and there should be things that make all kinds of people happy. So let’s just jump right in!
New Features
Okular now lets you digitally sign documents! Note that this feature makes use of a digital signature, not a picture of your handwritten signature. This feature was sponsored by the Technical University of Dresden (TU Dresden) (Albert Astals Cid, Okular 21.04)
Kate and other KTextEditor-based apps now have a new feature to swap the selected text with the top item in the clipboard (Christoph Cullmann, Frameworks 5.78)

All KDE software now supports the AV1 image format when the libavif library is installed, including displaying thumbnails in Dolphin and other apps (Daniel Novomeský, Frameworks 5.78)
Bugfixes & Performance Improvements
Dolphin no ever gets in a situation where it always tries to execute executable JavaScript files instead of opening them, when in a different context you’ve previously told it to always execute executable files (Ahmad Samir, Dolphin 20.12.1)
Fixed a common crash-on-launch bug in Dolphin and a case where Dolphin could crash when you open a new tab while there was text in the search field (Anthony Fieroni, Dolphin 20.12.1)
Dolphin no longer crashes when you try to drag a disk in the Places panel (Chris Holland, Dolphin 20.12.1)
Elisa’s “Force Filesystem Indexing” option is now remembered in the config window correctly (Matthieu Gallien, Elisa 20.12.1
Hugely increased the performance and speed of searching through large documents in Kate (Waqar Ahmed, Kate 21.04)
Kate’s Quick Open panel now always opens the correct item (Waqar Ahmed, Kate 21.04)
Improved the character placement in various command-line apps run using Konsole (Oswald Buddenhagen, Konsole 21.04)
The Emoji selector once again opens to display its “Recent” page (David Redondo, Plasma 5.20.5)
Improved compatibility with multi-monitor setups using different scale factors for each monitor in the Plasma Wayland Session (Vlad Zahorodnii, Plasma 5.21)
When you Alt+Tab to an XWayland window in the Plasma Wayland session, mouse wheel scrolling now always works properly in the window (Andrey Butirsky, Plasma 5.21)
The Global Menu applet now works properly in the Plasma Wayland session for XWayland windows (Fabian Vogt, Plasma 5.21)
The System Settings Users page no longer fails to set an avatar image when given a very large file; it now resizes it to fit (Jan Blackquill, Plasma 5.21)
The Lock/Logout applet once again works properly (David Edmundson, Plasma 5.21)
KRunner now correctly evaluates single-digit factorial expressions (Alexander Lohnau, Plasma 5.21)
The KGlobalAccel daemon no longer crashes–either once or repeatedly–when logging out of your user account or shutting down the computer (David Edmundson, Plasma 5.21)
Fixed the most common crash afflicting all KDE software: when graphics drivers are updated but before the system is restarted, and hardware acceleration is no longer available. Now the affected software will fall back to software rendering rather than crashing (Piotr Henryk Dabrowski, Frameworks 5.78)
Fixed one of the most common ways that an app could crash while downloading or updating Get New [Thing] content, and a less common-way that it would happen (Dan Leinir Turthra Jensen, Frameworks 5.78)
Plasma panels no longer show a weird black line when compositing is disabled (David Edmundson, Frameworks 5.78)
The file dialogs are now capable of opening files whose name begins with a colon (Ahmad Samir, Frameworks 5.78)
Custom shortcuts set to activate Plasma applets are no longer sometimes lost after rebooting (David Edmundson, Frameworks 5.78)
Improved the efficiency of Plasma’s SVG caching system, leading to a small but measurable performance improvement everywhere throughout Plasma (Marco Martin, Frameworks 5.78)
The Plasma calendar widget no longer lets you try to display negative years, which would make Plasma crash (me: Nate Graham, Frameworks 5.78)
User Interface Improvements
In Kate’s tab switcher panel, you can now close the currently selected document by hitting the Ctrl+W keyboard shortcut (Waqar Ahmed, Kate 21.04)
The System Settings Desktop Session page has had its user interface rewritten in QML for a cleaner, more modern appearance (Carl Schwan, Plasma 5.21):

Reverted the automount defaults changes announced last week because the new Disks & Devices behavior makes them largely unnecessary (me: Nate Graham, Plasma 5.21)
System Settings’ Screen Locking and Compositing pages now support the “Highlight Changed Settings” feature (Cyril Rossi, Plasma 5.21)
Re-added the option to make the Disks & Devices popup not automatically open when a new device is plugged in, because people articulated reasonable and valid use cases for it (me: Nate Graham, Plasma 5.21)

Made a few more tweaks to the Audio Volume applet, including moving the tab bar to the bottom, always hiding inactive devices, and moving all the toolbuttons up to the header row, as with other applets in Plasma 5.21 (me: Nate Graham, Plasma 5.21):

On Discover’s reviews sheet, datestamps for individual reviews are now displayed using a format appropriate for your locale (Tabor Nagy, Plasma 5.21)
On Discover’s “Updates” page, the position of the “Update” and “Check for Updates” actions has been swapped (me: Nate Graham, Plasma 5.21):

You can now enter relative paths in the URL Navigators used in various KDE apps. For example if you’re inside your home folder, you can enter “Documents” into the URL navigator and be taken there as expected (Ahmad Samir, Frameworks 5.78)
How You Can Help
Have a look at https://community.kde.org/Get_Involved to discover ways to be part of a project that really matters. Each contributor makes a huge difference in KDE; you are not a number or a cog in a machine! You don’t have to already be a programmer, either. I wasn’t when I got started. Try it, you’ll like it! We don’t bite!
Finally, consider making a tax-deductible donation to the KDE e.V. foundation.