@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 
{
    LockAnnotation lock(::cs_main); 
    
    if (!CheckFinalTx(*tx))
        return false;
    int nDepth = GetDepthInMainChain(locked_chain);
    if (nDepth >= 1)
        return true;
    if (nDepth < 0)
        return false;
    if (!pwallet->m_spend_zero_conf_change || !IsFromMe(ISMINE_ALL)) 
        return false;
    
    if (!InMempool())
        return false;
    
    for (const CTxIn& txin : tx->vin)
    {
        
        const CWalletTx* parent = pwallet->GetWalletTx(txin.prevout.hash);
        if (parent == nullptr)
            return false;
        const CTxOut& parentOut = parent->tx->vout[txin.prevout.n];
        if (pwallet->IsMine(parentOut) != ISMINE_SPENDABLE)
            return false;
    }
    return true;
}
bool CWalletTx::IsEquivalentTo(const CWalletTx& _tx) const