To be able to support future private communication also on mobile and to offer on-chain W2W secure communication to the enterprise sector an application-specific blockchain is needed. A blockchain that will be used only for its one and only purpose, processing communication transactions. New modern blockchains bring new scaling models such as Tron SideChains, Avalanche Subnets, Polkadot Substrates or Cosmos Interchains. Designed to be application-specific, these new sub-blockchain technologies could be the answer that we are looking to support dMail & dChat fast finality and low-cost transactions (i.e. one message = one transaction).