Ethereum co-founder Vitalik Buterin says the blockchain’s highly anticipated ‘merge’ will happen in August

After years of delays, Ethereum co-founder Vitalik Buterin confirms that the “merge” will finally happen this summer.

“If there are no problems, then the merge will happen in August,” Buterin said at the ETH Shanghai Web 3.0 Developer Summit on Thursday.

The merge is a highly anticipated upgrade to Ethereum that, if all goes smoothly, will shift the major blockchain from a proof-of-work mechanism to proof-of-stake.

Currently, Ethereum relies on a proof-of-work model, where miners race to complete complex puzzles to validate transactions. This requires a lot of computer power and energy. In shifting to proof-of-stake, where transactions are validated by those who contribute, or “stake,” to the network, Ethereum is supposed to become more eco-friendly and efficient.

This is a massive change, with much at stake.

“Of course, there's always a risk of problems. There's also a risk of delays,” Buterin said.

If such problems or delays arise, the merge might be pushed to September or October, he said.

Ethereum developers have worked on the shift to proof-of-stake for the last seven years, but the merge has been frequently delayed. This has convinced naysayers that the merge is unlikely to happen. Nonetheless, “the merge, at this point, is looking like it’s very close to happening,” Buterin said. “Ethereum will finally become a proof-of-stake network.”

Buterin’s comments come after Ethereum developers confirmed Ropsten, one of Ethereum’s key test networks, will undergo the merge on June 8.

“This will be a major test, larger than any of the tests that we have done before,” Buterin said of the upcoming Ropsten merge test.

If all goes well with Ropsten, “the likely plan is for the merge to happen in the summer,” Buterin said.

This story was originally featured on Fortune.com