V2: From 28 Dec 2025, 17% (0% before) fees on Ethereum shared to buy back and burn UNI, From 8 Mar 2026, 17% (0% before) fees on Optimism, Arbitrum, Base, Zora, XLayer chains shared to buy back and burn UNI (Tracked combined in Uniswap V3 adapter). V3: From 28 Dec 2025, a portion of fees a collected to buy back and burn UNI on Ethereum, From 8 Mar 2026, on Optimism, Arbitrum, Base, WC, Zora, XLayer, From 2 Jun 2026, on Polygon, BSC, Celo. V4: No revenue for UNI holders