Hydrogenesis is an object-oriented, high-level language for implementing DPROGs, which are decentralized programs run on the Fluidity blockchain and used for a number of purposes related to the Fluidity blockchain, Flow, and any other coins and DPROGs hosted by Fluidity.
With Hydrogenesis, you can create DPROGs for uses such as digital currency, decentralized exchange, voting, crowdfunding, blind auctions, games, and an assortment of other programs.
Hydrogenesis does not allow for any calls from internet data due to the nature of the blockchain, the existence of offline (cold) wallets, and the potential for malicious users to change their code remotely without it needing to be confirmed by the Fluidity blockchain network. The Fluidity blockchain therefore allows DPROGs to invoke other DPROGs, which may be constantly fed data by users that submit the data to the DPROG address through the Fluidity blockchain.
When deploying DPROGs, you should use the latest released version of Hydrogenesis. This is because breaking changes as well as new features and bug fixes are introduced regularly.