Kubuntu 26.10 beta is on cdimage: Kubuntu 26.10 (Stonking Stingray) Beta
Codename Stonking Stingray. Feature freeze was 20 August, user interface freeze 10 September. The mandatory beta slipped from 24 September and landed 1 October. Final freeze is 8 October. Final release is 15 October.
Please test in a virtual machine or on a spare machine, not the disk you use for work. A useful report is one problem, exact steps, and a Spectacle screenshot if the UI is wrong. Plasma bugs: https://bugs.kde.org/ Packaging and ISO issues: Launchpad, against Ubuntu or Kubuntu. Attach the version string from About this System.
Separate from the beta: a mid-September Chromium update corrupted the fontconfig cache and crashed Plasma. Update Chrome or Chromium first. If the desktop is still broken, from a text login (Ctrl+Alt+F3): rm -rf ~/.cache/fontconfig then fc-cache -r, then reboot. Thread: https://www.reddit.com/r/Kubuntu/comments/1wo84kz/
Short video (beta, the font-cache note, Overview on Meta+W, Tokodon): https://youtu.be/fEN3N6NCdbc