Version 1.5 of Cardano's blockchain was released to its main net. This release introduces Daedalus 0.13.0, a new version of Cardano's wallet software, and Cardano SL 3.0.0, a new version of Cardano's blockchain protocol.
Version 1.5 is the last major release of the Byron development phase. Byron is considered a bootstrapping phase where a baseline is established such that users can trade and transfer Ada. It is one of three major phases in Cardano's development plan. The other two are Shelley, the next phase after Byron when Cardano becomes fully decentralized, and Gogeun, when smart contracts can run on Cardano.
Cardano 1.5 is important in preparing the Cardano blockchain for a transition to the Shelley development phase. The 1.5 update brings a new consensus protocol, Ouroboros BFT, which is a key transition step from the current protocol, Ouroboros Classic, to the Shelley era protocol, Ouroboros Genesis. Ouroboros Genesis should turn Cardano into a true decentralized and secure proof of stake blockchain.