The blocks in the blockchain were not limited originally. The block size limit of one megabyte was introduced by Satoshi Nakamoto in 2010, as an anti-spam measure. Eventually the block size limit of one megabyte created problems for transaction processing, such as increasing transaction fees and delayed processing of transactions that cannot be fit into a block.On 24 August 2017 (at block 481,824), Segregated Witness (SegWit) went live, introducing a new transaction format where signature data is separated and known as the witness. The upgrade replaced the block size limit with a limit on a new measure called block weight, which counts non-witness data four times as much as witness data, and allows a maximum weight of 4 megabytes. Thus, per computer scientist Jochen Hoenicke, the actual block capacity depends on the ratio of SegWit transactions in the block, and on the ratio of signature data. Based on his estimate, if the ratio of SegWit transactions is 50%, the block capacity may be 1.25 megabytes. According to Hoenicke, if native SegWit addresses from Bitcoin Core version 0.16.0 are used, and SegWit adoption reaches 90 to 95%, a block size of up to 1.8 megabytes is possible.