Here is the post from Rick Brewster himself.
Rick Brewster wrote:This update resolves some feature disparities in the Text tool between GDI (XP) and DirectWrite (Win7/Vista). It also improves overall performance, as well as the correctness and quality of the Move Selected Pixels tool, the Image->Resize function, and the Hue/Saturation adjustment.
As usual there are two ways to get it:
1. Download directly from the website, http://www.getpaint.net/ . There is no need to uninstall the old version; that will be taken care of automatically.
2. Preferred: Use the built-in updater from within Paint.NET. You can go to Utilities->Check for Updates, or you can wait for the following update dialog to show up automatically within the next week or so:

Changes and fixes since v3.5.1:
* All font face variants (e.g., Arial vs. Arial Narrow) are now available with the Text tool in Win7/Vista with DirectWrite.
* Bitmap font types (e.g. Courier, Terminal, Fixedsys) are now available with the Text tool in Win7/Vista.
* Fixed some bad text kerning with the Text tool at small font sizes when antialiasing was turned off.
* For the Image->Resize function, the quality, correctness, and performance of Bilinear and Bicubic sampling modes have been improved. Super Sampling also has some performance improvement.
* Improved the rendering quality for the Hue/Saturation adjustment. Also made a new icon for it.
* Fixed many subtle rendering issues with the Move Selected Pixels tool. These were apparent when flipping or rotating a selected area.
* Fixed: The Line/Curve tool was applying pixel snapping to the curve nodes, which caused lines to "bend" when using the Shift key to constrain the angle.
* Fixed some extraneous CPU usage related to unnecessary or redundant thumbnail updates.
* Fixed a few dialogs that looked wrong with Aero glass with Remote Desktop or Virtual PC.
* Fixed a nasty memory leak with Flatten followed by Undo.
* Fixed some issues related to effects that took awhile to cancel. As it turns out, drag-and-drop was enabled at this time, which easily lead to crashes or hangs.
* Some Win7 systems could not detect that .NET 3.5 SP1 was installed, even though it was. A fallback detection function has been added.
* For plugin authors, the Effect class now has a pollable IsCancelRequested property. This can be used to improve responsiveness for expensive OnSetRenderInfo() implementations which are otherwise non-interruptible.
* For plugin authors, the Surface.FitSurface() method is now optimized to use multiple threads, which improves performance.
Looks pretty good from what I've seen so far.
Thanks to Rick for the quick update!
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