Katla is the most significant testnet we’ve had so far. Let’s see what Katla brings to the table and how you can get involved.

What’s new?

Here’s what’s new with Katla:

• Implemented Based Contestable Rollup (BCR) design with multi-proofs and SGX.

• Updated bridge implementation, refined bridge UI, and a new feature: NFT bridging!

• Updated testnet stats in block explorer and status page.

Let’s take a look at each of the points in more detail.

BCR implementation

Katla implements the Based Contestable Rollup (BCR), a rollup design that we introduced back in September 2023 at TOKEN2049 in Singapore. With Katla, we enable a multi-proof configuration with four tiers: Optimistic proofs, SGX proofs, SGX+zkEVM proofs, and guardian proofs as shown below.

To learn more about BCR and Taiko’s multi-proof design, please read this blog post.

On top of that, Katla’s code supports EIP-4844 (proto-danksharding) but this feature is turned off. When the base layer (Holesky) hard forks with EIP-4844, we’ll likely perform an upgrade to enable the use of blobs for data availability to reduce transaction costs.

All in all, Katla is still a based rollup and a type-1 ZK-EVM with exactly the same tokenomics design as in the Jólnir (Alpha-5) testnet. In other words, your application should work out of the box without any modifications.

Updated bridge

We’ve also fixed a few bugs in the bridge contract. The bridge app has also been reimplemented and NFT token bridging is now enabled. If your bridged operation on the destination chain failed, you can now claim back your bridged asset on the source chain. A complete changelog can be found here. And the bridge can be accessed here.

Besides the major updates detailed above, users, as always, will be able to swap, use various dapps deployed on Taiko, deploy contracts, run a node, propose, and prove blocks — all permissionlessly. To do all of that, visit our updated documentation here.

Updated block explorer

Katla also features an updated block explorer with new testnet stats.

For example, you can now see what’s the latest liveness bond, how many transitions were proved with what proof tier, and other stats.