Our fifth testnet is here! Jólnir (Alpha-5) brings new exciting adjustments to how proposing and proving works on Taiko.

Let’s see what those changes are and how you can participate!

New PBS-inspired proposing and proving design

Jólnir comes with a new, Proposer-Builder Separation (PBS)-inspired proposing and proving implementation. Here’s how it works:

• In Grímsvötn, a proposer needed to deposit some TTKO in order to propose a block;

• In Jólnir, proposers need to acquire a bond from provers to propose a block. Provers need TTKOj tokens (more on how to get them later) to deposit for the bond;

• If you run simple-taiko-node as a proposer or prover, your proposer will select your own local prover by default;

• However, proposers can also choose any prover from the open market (more on this later). Proposers will send a hash of the L2 block’s transaction list to an open market of provers, who offer a price that they’re willing to provide a bond for; proposers pay their provers off-chain;

• If provers prove their assigned blocks within the specified proof time target, they get their bond back and get to keep the upfront fee that they got from proposers off-chain;

• If provers fail to prove their assigned blocks within the specified proof time target, a portion of their bond is slashed; the blocks and the portion of the bond become open to the market again;

• The new system is used to ensure some liveness on the network. It also replaces staking pools so that we can simplify the design and allow prover pools to be implemented off-chain.

To participate in Jólnir, start with our freshly updated docs: https://taiko.xyz/docs.

How to get TTKOj

TTKOj has been distributed to A1 and A2 testnet proposers and provers (2.5 TTKOj per address). A3 and A4 testnet proposers and provers will also receive TTKOj shortly.

Additionally, proposers can provide bonds to themselves with their own prover; or find provers in the market (see this link to find the prover market table).

Other changes

Besides the new proposing/proving mechanism, Jólnir features a few other changes. These are:

• An updated bridge implementation and a new bridge UI design. We moved from TokenVault to separate vaults like ERC20Vault, ERC721Vault, and ERC1155Vault. Read about our bridge design here.

• An updated testnet stats page with line graph data in the block explorer. It’s now much easier to follow the stats; see it for yourself: https://explorer.jolnir.taiko.xyz/stats.

On top of that, you can use Taiko as a normal user (e.g., test our bridge and swap features), build dapps, and run a node. Everyone is invited in a permissionless way!

What about Grímsvötn L2 (A3) and Eldfell L3 (A4)?

As of today, we no longer support Eldfell L3. For Grímsvötn L2, we'll keep it alive through October 31st in order to support any projects migrating over.

However, we won't be officially supporting the network in terms of our documentation and frontend dapps like our bridge.

If you're an ecosystem project deployed on Grímsvötn L2 or Eldfell L3, check your emails — we’ve already reached out to you to help you with migrating to Jólnir!

Thank you for your participation and continuous support!

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