# Cardano Features

| Date    | Phase   | Era     | Slot Number | Epoch Number | Protocol Version | Ledger Protocol | Consensus Mechanism | Notes              |
| ------- | ------- | -------:| -----------:| ------------:| ----------------:| ---------------:| -------------------:| ------------------:|
| 2017/09 | Byron   | Byron   | 0           | 0            | 0,0              | -               | Ouroboros Classic   |                    |
| 2020/02 | Byron   | Byron   | 3801600     | 176          | 1,0              | -               | Ouroboros BFT       |                    |
| 2020/07 | Shelley | Shelley | 4492800     | 208          | 2,0              | TPraos          | Ouroboros Praos     |                    |
| 2020/12 | Goguen  | Allegra | 16588800    | 236          | 3,0              | TPraos          | Ouroboros Praos     |                    |
| 2021/03 | Goguen  | Mary    | 23068800    | 251          | 4,0              | TPraos          | Ouroboros Praos     |                    |
| 2021/09 | Goguen  | Alonzo  | 39916975    | 290          | 5,0              | TPraos          | Ouroboros Praos     |                    |
| 2021/10 | Goguen  | Alonzo  | 43372972    | 298          | 6,0              | TPraos          | Ouroboros Praos     | intra-era hardfork |
| 2022/09 | Goguen  | Babbage | 72316896    | 365          | 7,0              |  Praos          | Ouroboros Praos     | Vasil HF           |
| 2023/02 | Goguen  | Babbage | 84844885    | 394          | 8,0              |  Praos          | Ouroboros Praos     | Valentine HF |