New in the SumatraPDF [pre-release builds](https://www.sumatrapdfreader.org/prerelease):

## Open Markdown files

SumatraPDF can open and view Markdown documents (`.md`, `.markdown`), rendered as formatted text with GitHub Flavored Markdown (tables, task lists, strikethrough). The installer registers the file association. This comes with an update of the MuPDF rendering engine to 1.28.

![A Markdown document with a table, a task list and strikethrough text](https://files.sumatrapdfreader.org/assets/sumatrapdf/changelog/img/markdown-gfm-9d11.png)

## Fill in PDF forms

PDF forms can be filled in directly: click checkboxes and radio buttons, type into text fields in place, pick values from combo boxes and list boxes, and move between fields with `Tab` / `Shift + Tab`. Form calculations written in JavaScript run; turn PDF JavaScript off with the new `DisableJavaScript` advanced setting. Filled forms are saved like annotations, and the close prompt now says "Unsaved changes".

![A sign-up form: Jamie Rivera is typed into the Name field in place, Tab moves to the Bread combo box whose list drops down and Sourdough is clicked, typing 2 tickets makes the form's JavaScript fill in the total of 50 EUR, and the Vegetarian lunch checkbox is clicked](https://youtu.be/kErLPyubSjo)

## Save or discard from the tab context menu

Right-clicking a tab whose document has unsaved changes (filled forms, new annotations) shows **Save changes to existing PDF**, **Save changes to new PDF** and **Discard changes** at the top of the menu.

![Tab context menu of a document with a new highlight annotation, with Save changes to existing PDF, Save changes to new PDF and Discard changes at the top](https://files.sumatrapdfreader.org/assets/sumatrapdf/changelog/img/tab-menu-save-discard-128c.png)

## Match whole word in Find

The Find bar has a new **Match whole word** toggle next to **Match Case**, so searching `cat` won't match `category` (`CmdFindToggleMatchWholeWord`) ([#4295](https://github.com/sumatrapdfreader/sumatrapdf/issues/4295)).

![Find bar with Match whole word turned on: searching "we" highlights only the whole word, not "wet" or "weeks"](https://files.sumatrapdfreader.org/assets/sumatrapdf/changelog/img/find-match-whole-word-f15c.png)

## Smoother find-as-you-type

Find-as-you-type now waits briefly after you stop typing before searching (500 ms, or 1 s for 1-2 characters) instead of searching on every keystroke. Press `Enter` to search immediately ([#4626](https://github.com/sumatrapdfreader/sumatrapdf/issues/4626)).

## Go to next / previous favorite

New **Go to Next Favorite** and **Go to Previous Favorite** commands (`CmdGoToNextFavorite`, `CmdGoToPrevFavorite`, `Ctrl + K` command palette) jump to the nearest favorite page after or before the current page ([#3744](https://github.com/sumatrapdfreader/sumatrapdf/issues/3744)).

## Paste an image from the clipboard as a stamp

You can paste an image from the clipboard into a PDF as an image stamp annotation: right-click → **Annotations** → **Create Under Cursor** → **Image From Clipboard**, or **Create Image Annotation From Clipboard** (`CmdCreateAnnotImageFromClipboard`) in the command palette. The stamp is placed at the click point and selected so you can move or resize it ([#3671](https://github.com/sumatrapdfreader/sumatrapdf/issues/3671)).

![With a PAID picture on the clipboard, right-click on an invoice > Annotations > Create Under Cursor > Image From Clipboard puts it on the page at that spot, selected, and it is dragged below the total](https://youtu.be/8RBoMHK7ReY)

More: [changes from June 22, 2026](https://www.sumatrapdfreader.org/docs/Changelog-2026-06-22) and the [full changelog](https://www.sumatrapdfreader.org/docs/Changelog).