According To ETH Developer Tim Beiko London Aim For A Mid-July Mainnet Deployment Of 1559, 3198, 3238

He Explained:

“There were four specific EIPs we were considering alongside the already included ones (1559, 3198, 3238) for London: EIP-2537, EIP-2677, EIP-3403, and EIP-3074.

EIP-2677 was the simplest: small change, but no one strongly in favor and, given it would add testing overhead, we’re not adding it to London.

Then, we discussed EIP-3403. The EIP proposes to remove refunds from SSTORE and SELFDESTRUCT, except in a handful of cases. Because refunds can increase block gas consumption, and 1559 does too, limiting them in London was brought up as a security concern previously.

The challenge with 3403 lies in the except in a handful of cases: adding such logic to clients increases code complexity and is prone to bugs. OTOH, completely disabling refunds would be a very large breaking change, and was already rejected (EIP-3298).

So, VitalikButerin and MHswende have been working on a new proposal, which would lower gas refunds from SSTORE from 15k to 4.8k gas, remove SELFDESTRUCT refunds and lower the maximum extra execution from refunds from 1/2 to 1/5th of the block.

This proposal would achieve the goal of reducing block elasticity, disincentivizing things like gas token, and reduce implementation complexity relative to 3403. The EIP was discussed in more detail on the call, but should be formally created early next week.

Everyone on the call seemed favorable to the idea, but given there is no actual EIP to look at yet, clients will review it over the next week and we will make a decision about this on next Friday’s call.

Next up, we discussed EIP-2537, the BLS precompile. The champion asked what clients would like to see to include it in London, and there were two potential concerns: first, the desire to move to a new library, which would require more testing, and second, some gas price changes.

Keep London lean, and aim for a mid-July mainnet deployment. Only 1559, 3198, 3238 and the to-be-created refund EIP.

Keep working on the Merge in parallel to London and aim to ship it ASAP. When London is done, start working on another small feature fork, Shanghai.

Shanghai should really be “only the things that we wanted in London but couldn’t make it”. If it is ready before the Merge, we ship it first. If the Merge is ready before, everyone is OK delaying Shanghai (and doing the extra technical work to adapt it) to after the merge.

So, to summarize, we’re looking at mid-July for London, and the fork will contain EIPs 1559, 3198 (BASEFEE opcode), 3238 (Ice Age pushback), and very likely a to-be-created EIP addressing the refunds issue which we’ll discuss next call.”

Source: https://twitter.com/TimBeiko/status/1385614558883041284