What it reads
Sumatra PDF opens PDF, ePub, MOBI, CHM, XPS, DjVu, CBZ, and CBR files. The interface is minimal by design: no toolbars, no sidebar, no update nag screens. It starts fast and stays out of the way.
Portability and system requirements
The portable build is a single executable that runs from a USB drive without writing to the registry. The installer version adds file associations and Start menu entries. Supported operating systems include Windows 10, Windows 8, Windows 7, Vista, and XP. Both 32-bit and 64-bit builds are available.
Source and updates
The project is open source. Source code and contribution guidelines are hosted on the project site. Version history documents changes between releases. Previous versions remain accessible for compatibility testing.
Why it matters for regulated practices
A lightweight reader with no telemetry, no auto-update service, and no registry footprint reduces attack surface on workstations that handle confidential matter files or patient records. Portable execution means it can be vetted once and deployed from a trusted network share without per-machine installation.