# Prerequisite software

The software that DITA-OT requires depends on the output formats you want to use.

## Software required for core DITA-OT processing

DITA-OT requires the following software applications:

Java Development Kit (JDK) or Java Runtime Environment (JRE)
  DITA-OT 4.4 is designed to run on Java version 17 or later and built and tested with the Open Java Development Kit (OpenJDK). Compatible Java distributions are available from multiple sources:
  - You can download Oracle distributions from oracle.com/java under commercial license.
  - Eclipse Temurin is the free OpenJDK distribution available from adoptium.net.
  - Free OpenJDK distributions are also provided by Amazon Corretto, Azul Zulu, and Red Hat.
  - Java versions are also available via package managers such as Chocolatey, Homebrew, or SDKMAN!
  Note:
  This is the only prerequisite that you need to install. All other required software is provided in the distribution package, including Apache Ant™ 1.10.15, Saxon 12.9, and ICU for Java 77.1.

## Software required for specific transformations

Depending on the type of output that you want to generate, you might need the following applications:

HTML Help Workshop
  Microsoft no longer provides the software required for generating Compiled HTML Help (.chm) files. You can download an archived copy of the HTML Help Workshop from the Internet Archive’s Wayback Machine at web.archive.org.
XSL-FO processor
  Required for generating PDF output. Apache™ FOP (Formatting Objects Processor) 2.11 is included in the distribution package. You can download other versions from xmlgraphics.apache.org/fop. You can also use commercial FO processors such as Antenna House Formatter or RenderX XEP.