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

## Back / Forward toolbar buttons

The toolbar has Back and Forward buttons. Navigation history now also includes places you scrolled to and stayed on, not only table of contents and link jumps.

![Back and Forward buttons in the toolbar, with the Back tooltip](https://files.sumatrapdfreader.org/assets/sumatrapdf/changelog/img/back-forward-buttons-1f9e.png)

## Toggle citation hover preview

**Toggle Citation Hover Preview** (`CmdToggleHoverPreview`, command palette) turns the citation hover preview on or off. The `CitationHoverDelay` setting sets how long you hover before it appears (`-1` turns it off).

## View mode hints and sidebar fonts

Switching the view mode with `Ctrl + 6/7/8` shows a short popup naming the new mode ([#5464](https://github.com/sumatrapdfreader/sumatrapdf/issues/5464)). Sidebar fonts scale with the app's font size settings ([#5564](https://github.com/sumatrapdfreader/sumatrapdf/issues/5564)).

## -for-testing command-line flag

`-for-testing` starts a separate instance that doesn't restore the previous session and doesn't save settings. It is useful for quick tests.

More: [changes from June 12, 2026](https://www.sumatrapdfreader.org/docs/Changelog-2026-06-12) and the [full changelog](https://www.sumatrapdfreader.org/docs/Changelog).