### Motivation

This should be done before the branch-off, and can be done by anyone, as the steps are  reproducible and reviewable.

### Possible solution

Follow the documentation: https://github.com/bitcoin/bitcoin/blob/master/doc/release-process.md#before-branch-off

### Useful Skills

* Compiling Bitcoin Core from source
* Running the C++ unit tests and the Python functional tests
* ...


### Guidance for new contributors

Want to work on this issue?

For guidance on contributing, please read [CONTRIBUTING.md](https://github.com/bitcoin/bitcoin/blob/master/CONTRIBUTING.md) before opening your pull request.

public:
    CTestNetParams() {
        m_chain_type = ChainType::TESTNET;
        consensus.signet_blocks = false;
        consensus.signet_challenge.clear();
        consensus.nSubsidyHalvingInterval = 210000;
        consensus.script_flag_exceptions.emplace( 
            uint256S("0x00000000dd30457c001f4095d208cc1296b0eed002427aa599874af7a432b105"), SCRIPT_VERIFY_NONE);
        consensus.BIP34Height = 21111;
        consensus.BIP34Hash = uint256S("0x0000000023b3a96d3484e5abb3755c413e7d41500f8e2a5c3f0dd01299cd8ef8");
        consensus.BIP65Height = 581885; 
        consensus.BIP66Height = 330776; 
        consensus.CSVHeight = 770112; 
        consensus.SegwitHeight = 834624; 
        consensus.MinBIP9WarningHeight = 836640; 
        consensus.powLimit = uint256S("00000000ffffffffffffffffffffffffffffffffffffffffffffffffffffffff");
        consensus.nPowTargetTimespan = 14 * 24 * 60 * 60; 
        consensus.nPowTargetSpacing = 10 * 60;
        consensus.fPowAllowMinDifficultyBlocks = true;
        consensus.fPowNoRetargeting = false;
        consensus.nRuleChangeActivationThreshold = 1512; 
        consensus.nMinerConfirmationWindow = 2016; 
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].bit = 28;
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime = Consensus::BIP9Deployment::NEVER_ACTIVE;
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
        consensus.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].min_activation_height = 0;