@jonasschnelli wrote in #14979:
> #14573 broke < Qt5.6 compatibility due to calling the lambda version of `addAction` that was added in Qt5.6.

We currently [support](https://github.com/bitcoin/bitcoin/blob/master/doc/dependencies.md) QT >=5.2, but hardly anyone tests with that. If we make one of the Travis machines use it, we should have a better change of catching this.

See also discussion about minimum QT version in #13478 
const CCoinControl& coin_control,
        bool sign,
        int& change_pos,
        CAmount& fee,
        std::string& fail_reason) override
    {
        auto locked_chain = m_wallet.chain().lock();
        LOCK(m_wallet.cs_wallet);
        auto pending = MakeUnique<PendingWalletTxImpl>(m_wallet);
        if (!m_wallet.CreateTransaction(*locked_chain, recipients, pending->m_tx, pending->m_key, fee, change_pos,
                fail_reason, coin_control, sign)) {
            return {};
        }
        return std::move(pending);
    }
    bool transactionCanBeAbandoned(const uint256& txid) override { return m_wallet.TransactionCanBeAbandoned(txid); }
    bool abandonTransaction(const uint256& txid) override
    {
        auto locked_chain = m_wallet.chain().lock();
        LOCK(m_wallet.cs_wallet);
        return m_wallet.AbandonTransaction(*locked_chain, txid);
    }
    bool transactionCanBeBumped(const uint256& txid) override
    {
        return feebumper::TransactionCanBeBumped(&m_wallet, txid);
    }
    bool createBumpTransaction(const uint256& txid,