Found this on their site

What about DATG?
DATG (Datum Genesis Token) was distributed exclusively during the Presale to early contributors and will not be directly used in the Datum App or Network. All DATG holders will instead receive the DAT token equivalent as outlined above. DATG tokens are currently not transferable and we do not have any plans in the near future to make them transferable, however do not throw the private keys to your account holding DATG away just yet, we may have some utility in store for them in the future to reward early backers.

Distribution of DAT to Presale contributors
DAT tokens will be distributed to all DATG holders automatically at the same time as all Token Sale contributors are receiving their DAT Tokens (the distribution is scheduled to happen between 4th December and 11th December). The DAT Tokens will be sent automatically to the same ETH Address that you used to participate in the Presale.

https://blog.datum.org/datum-presale-58883067371b