Stage 5

Stage 5 features

Status: Testing underway

During the Stage 5 test phase, the Mumbai network was fully deprecated, forcing the test dApp to transition to Sepolia.

For the current dApp, see the entrypoint. Note that, each stage's entrypoint is deprecated in favor of the next stage.


Stage 5 introduces two core functionalities with some extra details on the impact to UTXO Selection:

Integrations with 3rd party Bundlers

Panther has integrated with Etherspot’s Skandha ERC4337 Bundler service to send transactions to the blockchain. Users will now have an option to select (Bundler = YES / NO) before submitting their transactions.

  • Bundler = YES will send transactions via the Bundler services in which case the network gas cost is deducted from the balance of their Panther Gas Account.

  • Bundler = NO will send transactions directly from user's EOA (externally owned account, i.e. the connected MetaMask wallet) and the network gas fee is paid from that wallet in the native gas token.

Introducing faster transactions

Panther uses zMiners to process newly created UTXO in batches instead of individual UTXO commitment updates enabling lower gas cost for the transactions involved in this batch.

UTXO selection update

Stage 5 enables UTXO's to be processed individually as opposed to a batch enabling near instant spending of the new UTXO’s. This reduces the wait time to process the batch but comes with an extra cost. Technically this is referred to using a ‘Taxi’ (from the Taxi tree where the UTXO gets added).

The user can choose between the Regular Processing (taking the bus) and Fast Processing (taking the taxi) from the toggle available under the Fee section before submitting any transaction.

As a result of the above change to process newly created UTXO in two modes, some UTXOs may not be immediately available to be used in another transaction (or spent). This restriction applies only for a short period of time (a few minutes) until the Bus Queue or the Miner has processed the next queue. These restriction are:

  • UTXOs created by two separate FAST transactions can't be spent together

  • UTXOs created by FAST transactions and a REGULAR transactions cannot be joined together

Again, it is important to note that these restrictions apply only for a very small duration of time after the creation of a FAST transaction and it pertains to how soon you can spend a UTXO created by a FAST transaction and join it with other available UTXO’s. It has nothing to do with the FAST transaction in itself but the output of this transaction to be used in the next transaction.

User testing flow

Bundler selection

  1. Navigate to any the transaction screen (currently Deposit, Transfer, and Withdraw) and check the new development in the Fees section.

  2. A new Bundler toggle is available for selection between a YES or a NO:\

Processing selection

  1. Navigate to any of transaction screen (currently Deposit, Transfer, and Withdraw) and check the new development in the Fees section.

  2. A new toggle to select Processing Type is now available.\

UTXO selection update

Notes: The fee functionality is not completely integrated in this version yet so the testing expectation is that transactions are processed via Bundlers and users also able to process FAST transactions. The deduction of fees and the full calculations of fees will be implemented with Stage 6.

What next?

For more information on zMiners, see the Stage 0 blog.

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