The DASH7 Alliance Protocol Specifications
The Dash7 version 1.1 is the current specification which is voted by the Alliance.
You may download it here.
If you want to join the discussion further specification development, you are welcome to become a member and join the Protocol Action Group.
DASH7 Alliance Protocol Stack Implementations
OSS-7: Open Source Stack for DASH7
Open source stack maintained by the University of Antwerp, more info here.
It contains a stack but also tools such as a Wireshark dissector for DASH7.