Ethereum Fusaka Upgrade to Boost ETH Blob Capacity from Dec 3
Ethereum Fusaka upgrade is scheduled to activate on mainnet on December 3, 2025, marking the first phase of a multi-stage increase in blob capacity per block. Following initial boosts, further capacity hikes are planned for December 17 and January 7. The upgrade deploys data availability sampling and multiple EIPs to improve backend performance, reduce bandwidth requirements, and accelerate Layer 2 rollups. Stability tests on Fusaka Devnet-5 revealed installation issues and a critical ckzg library bug—fixed by Ethereum researcher Justin Traglia—prompting a Devnet-6 launch and migration to public testnets before mainnet deployment. During stress tests, the Prysm client generated orphan blocks under high load, highlighting the need for efficiency enhancements. Since the Dencun upgrade, average blob usage has risen from 0.9 to 5.1 per block, underlining growing L2 activity. Meanwhile, a record 2.6 million ETH stands in the validator exit queue, raising short-term sell-pressure concerns despite assurances that the prolonged withdrawal process is essential for network security. Traders should watch for lower gas fees, higher throughput, and increased rollup-driven volume as the Ethereum Fusaka upgrade rolls out.
Bullish
The Ethereum Fusaka upgrade is likely bullish for ETH. In the short term, improved blob capacity and backend optimizations should reduce gas fees and increase transaction throughput, potentially spurring higher rollup activity and trading volumes. Although a record ETH exit queue raises some sell-pressure concerns, these are offset by strengthened network security and efficiency. Over the long term, enhanced Layer 2 scalability and lower transaction costs can drive broader adoption and higher demand for ETH, supporting price appreciation.