Uniswap has licensed the third iteration of its code bank in an apparent move to ward off would-be copycats.

The white paper for v3 of the decentralized exchange (DEX) was released Tuesday. In a possible nod to rival project SushiSwap – which copied Hayden Adams’ creation bit by bit – the Brooklyn, N.Y.-based team’s blog post included one section detailing a “business source license” that acts as a time delay for commercial use of the code “for up to two years.” 

After that point, the code will remain in an open-source GPL license “into perpetuity” for any project to build on or take from.

With the license, no one can copy Uniswap’s code base wholesale, although it’s unclear if aspects of the code bank can be copied. It remains a large departure from the open-source nature of most cryptocurrency projects.

“We strongly believe decentralized financial infrastructure should ultimately be free, open-source software,” Uniswap wrote. “At the same time, we think the Uniswap community should be the first to build an ecosystem around the Uniswap v3 Core codebase.”

The license harkens back to the August height of “DeFi Summer” when pseudonymous developer Chef Nomi released a copy of the Uniswap software with a token. The token acted as an incentive for pulling liquidity away from Uniswap and into Chef Nomi’s project, SushiSwap.

Called “vampire mining,” SushiSwap’s liquidity games forced Uniswap to launch a token itself in September. That token is now the eighth-largest cryptocurrency when measured by market cap, according to Messari.

The two projects have since gone in different directions. 

SushiSwap’s SUSHI token earns yield for every trade conducted on the exchange, leading to increased liquidity over its rival exchange. Uniswap, on the other hand, has focused more on core technical issues such as liquidity provisioning and impermanent loss.