Prague support is now live on Alpen testnet

Today, we're releasing Alpen's new Prague-compatible testnet. This milestone moves Alpen closer to its mainnet specifications and gives the Alpen community a more up-to-date, future-facing environment to build, test, and ship their Bitcoin-based applications. By updating Alpen to support Pectra’s execution layer specs (Prague), we make it easier for EVM ecosystem teams to bring financial applications to Bitcoin with minimal changes.‍

Important: On December 22, two weeks from today, Alpen's first Shanghai-compatible public testnet will be sunset and all associated infrastructure will be wound down. To avoid outages, all teams must update config files and migrate any apps from the Shanghai-compatible testnet to the new Prague-compatible testnet. Technical details for the new testnet can be found below.

What’s in the new Alpen testnet

This network update includes several important changes for node operators and smart contract developers:

• Reth update: We’ve bumped our Reth version from v1.1.5 → v1.8.2
• Migration to RSP for ZK proofs: Block execution now uses Reth Succinct Processor (RSP) for generating ZK proofs
• Pectra activation: The new testnet activates Prague-compatible specs for the EVM execution environment, with two exceptions:
  
  • Type 3 transactions are not supported
  • There is no KZG precompile as defined in EIP-4844 for blob transaction verification

Blobs are an Ethereum-specific feature and are not used by Alpen due to its Bitcoin-centric architecture. Learn more at Alpen Design Rationale.

Breaking changes and required actions

This update requires a network regenesis, which introduces several changes for developers and infrastructure providers:

• All state is reset: accounts, balances, and state from the previous testnet are erased
• New chain ID: all wallets must add a new Alpen Testnet network with chain ID 8150
• All smart contracts must be redeployed
• Node operators must deploy the latest release
• A new bridge_pubkey must be set in the Alpen CLI config files
• A new signet challenge must be set in the Bitcoind node configuration file

Timeline and migration plan

We’ve planned a staged rollout to minimize outage risk and give impacted teams time to deploy on the new testnet before the previous testnet is sunset.

December 4, 2025

• The new Prague-compatible testnet goes live at https://rpc.pectra-testnet.alpenlabs.io with chain ID 8150
• Teams can deploy infrastructure, request testnet tokens, add liquidity, and begin testing

December 22, 2025

• The previous Shanghai-compatible testnet shuts down (sequencer stops, nodes go offline)
• Expected downtime for DNS and TLS certificates propagation
• All *.testnet.alpenlabs.io endpoints are redirected to point to the new Prague-compatible testnet
• Existing endpoint at https://rpc.pectra-testnet.alpenlabs.io remains available as an alias

January 21, 2026

• The endpoint at https://rpc.pectra-testnet.alpenlabs.io is disabled; all activity should move to the canonical *.testnet.alpenlabs.io endpoints

How to get started

The following steps outline how to maintain uptime throughout this testnet update:

1. Review the network specs
   
   • You can find all the relevant network parameters, endpoints, and configuration details in the RPC page of our docs
   • Use these docs to identify any breaking changes and adjustments needed by your application
     
2. Update your tooling to the new endpoints
   
   • Until December 22: Configure your development tooling to point at rpc.pectra-testnet.alpenlabs.io
   • After December 22: Configure your development tooling to point at rpc.testnet.alpenlabs.io
   • Configure your wallets to point at the new chain ID 8150
   • Create your accounts and contact Alpen to receive coins on the new testnet (faucet may have limited initial availability)
     
3. Redeploy contracts and migrate applications
   
   • Deploy your contracts to the Prague testnet
   • Update your frontends and backends on time for the December 22 switch
   • Add planned downtime for the application migration on December 22
     
4. Inform your users
   
   • Make it clear that accounts and balances on the currently running Alpen testnet will be erased on December 22. All accounts will restart from zero
   • Users should remove current Alpen testnet from their wallet and add the new one with chain ID 8150

Looking ahead to mainnet

We’re on this journey to mainnet and beyond together! We request feedback from you along this journey, which will make the experience better for everyone. Please join Discord or Telegram to receive any real-time updates, ask questions, and share your feedback.

Alpen is open source! We welcome contributions across protocol, infra, tooling, and documentation. Get started here.