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AMM v2

ETHPort

This is the last version before the following features are added:

• AMM v2 (3.8)
• ETHPort (3.7)
• v3.9

• It can mix and batch process different types of layer-2 transactions into the same block, which greatly improved the relayer's batching efficiency and reduced the ZKP prover cost.
• Explicit account activation for layer-2 is no longer required. All Ethereum addresses are activated by default thus can receive funds on layer-2.
• The capacity is now much larger. It supports up to 2³² (~4.3 billion) accounts, 2¹⁶ (65536) tokens, and ²³² (~4.3 billion) order IDs.
• It supports much flexible deposits and withdrawals. Now a user can deposit to another user's layer-2 account and can withdraw to any Ethereum address on layer-1.
• It also supports different layer-2 transaction authentication using ECDSA signature, EdDSA signature, and onchain hash. 
• It supports Agents - an Agent is smart contracts authorized by a user to act on behalf of the user to transact and interact with Loopring. The Agent design enables extensibility.
• All withdrawals are potentially fast-withdrawals as long as there are liquidity providers willing to "accelerate" these withdrawals. All fast withdrawals can even be further "speed up" while pending in Ethreum's mempool. Fast withdrawal is built using the Agent design.
• Layer-2 AMM settlement support. Loopring supports the Balancer's curve: A^a * B^b* … *Z^z = K . Loopring 3.6 allows the very flexible design of the AMM managing contracts on layer-1. These AMM contracts are also Loopring Agents.
• Layer-2 transfers can be parallel -  they can settle "out of order" to enable scenarios such as red-envelop distribution.
• Maintainance mode is removed and Shutdown mode no longer requires a complete state revert.
• All fees are "max fees", which allows the operator to offer users a fee discount.
• Dual Authoring is back. With Dual Authoring, transfers can omit the recipient address and whoever gets the first Dual Authoring private key can claim the transfer. This enables the payee-scans-payer payment scenario, especially when the payer has no network connection.
• Orders can specify a target address to match with. This is a protocol-level security guarantee for OTC trades.
• Deposit fees and token registration fees have been removed.

See here for a more detailed list of changes compared to 3.1: https://github.com/Loopring/protocols/blob/master/packages/loopring_v3/security_audit/LoopringV3_6_vs_V3_1.pdf

Hebao's first mainnet release with bug fixes and improvements based on internal and external audits.