docs/Community/Downloads.md

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# Downloads

## [Signing Keys](https://downloads.apache.org/datasketches/KEYS)

It is essential that you verify the integrity of release downloads. See [instructions here.](https://www.apache.org/dyn/closer.cgi#verify)

## Latest Source Zip Files

{% include downloadsInclude.txt %}

## Download Java Jar Files

From [Maven Central](https://central.sonatype.com/search?smo=true&namespace=org.apache.datasketches).

### Use with Maven

If you are developing using Maven and want to use, for example, datasketches-java, add the following dependencies to your pom.xml file:

```xml
<dependency>
  <groupId>org.apache.datasketches</groupId>
  <artifactId>datasketches-java</artifactId>
  <version>9.0.0</version>
</dependency>
```

## Enabling Python

* First download the Python core above, then read the [Python Installation Instructions](https://github.com/apache/datasketches-python/blob/main/README.md)

## Download Earlier Versions

* [Recent ZIP Releases](http://archive.apache.org/dist/datasketches)
* [Older ZIP Releases](http://archive.apache.org/dist/incubator/datasketches)
* [Maven Central for Java Jar files](https://search.maven.org/search?q=g:org.apache.datasketches)

## Version Numbers

Apache DataSketches uses [semantic versioning](https://semver.org/). Version numbers use the form major.minor.incremental and are updated as follows:

* __major version__ for major new functionality and/or major API changes.  For major API changes users should expect that there may be some API-incompatible changes.  This should be made clear in the release comments.
* __minor version__ for new functionality and scheduled bug fixes. These should be API compatible with prior versions.
* __incremental version__ for unscheduled bug fixes only.

All download files include a version number in the name, as in _apache-datasketches-java-1.1.0-src.zip_.
This same number is also in the top section of the pom.xml file and is the same number in the GitHub Tag associated with the GitHub-ID that
the release was generated from.


### Version History and Release Notes

Please use GitHub version history on the respective component repositories. There are several ways to access the release notes:

#### Direct link from the GitHub page

* In the right-hand column click on **Releases**.

#### From the **tags** button on the GitHub page

* Click on **tags**
* Select **Releases**

#### From the **Branches (master)** button

* Click on the branch icon **[master]**
* Click on **[Tags]**
* At the bottom of the pop-up click on **[View all tags]**
* Click on **[Releases]**

#### Or, you can go directly by apending `/releases` to the URL as in

* `https://github.com/apache/datasketches-java/releases`


## Release Philosophy

These are fully tested, production quality releases, and hopefully as bug-free as humanly possible.
However, the code is continuously evolving and improvements in performance, documentation, additions
to the API, and bug fixes do occur.  When enough of these build up, especially for bug fixes or
performance improvements, a new release will be issued and the **minor version**
digit will be incremented.  The **incremental** digit will only be used for unscheduled bug fixes as stated above.

As stated above, the **major** digit is being reserved for major refactorings of the library where backward API
compatibility may not be guaranteed.

For the repositories that depend on java core, such as *datasketches-hive* and *datasketches-pig*,
the version number may be incremented just to be in sync with the java core repository,
and may not reflect any actual code changes other than a change in the pom.xml to reflect the new
dependency. Please refer to the release notes for that version.

### Binary Compatibilty

We try as much as possible to maintain *forward binary compatibility* of serialized (stored) sketch images.  For example, a Java Theta Sketch stored as a binary image using version 0.1.0 (Aug, 2015) can be read and merged into a C++ Theta Union version 1.2.0 (Jan, 2020).  The languages can be swapped in this scenario, but the versions cannot be.