This release is going pretty smoothly! I just had to fix a few small things that were pointed out in the forum thread for the alpha release, and get the translations up-to-date.
To get this update, make sure you have "Also check for pre-release (beta) versions" enabled in Settings, and then click on the Check Now button. (Unfortunately alpha/beta releases are not currently available for the Microsoft Store version of the app).
You can also download and install this build directly on the forum.
Changes since 4.2.15 alpha build 7683:
- Changed: In the Text tool, Ctrl+(Backspace, Delete, Arrow Keys) has been improved to work more like Microsoft Word. Thanks to @Bruce Bowyer-Smyth for the patch!
- Fixed: The sliders for color gradients (e.g. Colors form, some plugins) are now properly visible for the Light and Blue themes. Reported here: https://forums.getpaint.net/topic/117660-paintnet-4215-alpha-build-7683/?do=findComment&comment=579778
- Fixed: Some old plugins by Ed Harvey were not working. Reported here: https://forums.getpaint.net/profile/46943-toe_head2001/?wr=eyJhcHAiOiJmb3J1bXMiLCJtb2R1bGUiOiJmb3J1bXMtY29tbWVudCIsImlkXzEiOjExNzY2MCwiaWRfMiI6NTc5ODAxfQ==
paint.net blog 
Would it be possible to integrate a simple color switcher/picker in the resize canvas menu? I use paint.net virtually every day since Windows XP, and I frequently had to close the canvas resizer because I figured out too late that I picked the wrong color. And thank you for your work. I do not think I need to tell you, but you’re doing a truly outstanding job.