# Cortado Testnet Release

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With the release of [Gibraltar](https://docs.espressosys.com/network/releases/testnets/gibraltar-testnet-release) (testnet 4), the Cortado testnet is currently paused.
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In September 2023, we announced the Cortado release of Espresso.

The primary highlight of the Cortado release is the integration of a second rollup stack with Espresso: the [OP Stack](https://stack.optimism.io/). This integration is a direct result of the work that Espresso completed in [developing a leader election interface for the OP Stack](https://docs.espressosys.com/network/releases/testnets/cortado-testnet-release/op-stack-integration/optimism-leader-election-rfp), for which Espresso was awarded an Optimism RFP in July 2023. Details on the OP Stack integration can be found [here](https://docs.espressosys.com/network/releases/testnets/cortado-testnet-release/op-stack-integration).

We've deployed a public Cortado testnet, integrated with two rollups of different stacks: an OP Stack rollup (called Vienna, deployed in collaboration with [Caldera](https://caldera.xyz/)) and a Polygon zkEVM rollup. Instructions for interacting with this testnet can be found [here](https://docs.espressosys.com/network/releases/testnets/doppio-testnet-release/interacting-with-doppio).