DHL Versenden for Magento 1
The module for Magento 1 is attached to this article (see below).
In the future, it will also be available on the Magento Marketplace. DHL is currently working on this.
DHL Shipping for Magento 2
The module for Magento 2 can be found on Github.
For more details about its progress, please see this FAQ article.
DHL Intraship (deprecated)
The Intraship module has reached its End of Life. Users of the Intraship module need to migrate to DHL Versenden / Shipping.
For reference purposes, the last available Intraship module version is attached to this article (see below).
However, do NOT use this for new installations!
Here is a list of all documentations.