Ethereum co-founder Vitalik Buterin said on Thursday that Ethereum will be about 55% complete after the “merge,” when the network moves from proof-of-work (PoW) to a proof-of-stake (PoS) consensus system.

Proof of stake is much more secure than proof of work, but it does have its tradeoffs,” like weak subjectivity, Buterin said at the Ethereum Community Conference (EthCC) in Paris, Fortune reported. Buterin said the difference between Bitcoin and Ethereum is that Bitcoin is considered to be 80% complete in terms of development. Ethereum, on the other hand, is considered to be only about 40% complete at the moment, which will increase post-merge.
Last week, Ethereum developers announced that the merge will tentatively take place during the week of Sept. 19.