@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 
}
    
    if (mapKeyFirstBlock.empty())
        return;
    
    for (const auto& entry : mapWallet) {
        
        const CWalletTx &wtx = entry.second;
        if (Optional<int> height = locked_chain.getBlockHeight(wtx.hashBlock)) {
            
            for (const CTxOut &txout : wtx.tx->vout) {
                
                for (const auto &keyid : GetAffectedKeys(txout.scriptPubKey, *this)) {
                    
                    std::map<CKeyID, int>::iterator rit = mapKeyFirstBlock.find(keyid);
                    if (rit != mapKeyFirstBlock.end() && *height < rit->second)
                        rit->second = *height;
                }
            }
        }
    }
    
    for (const auto& entry : mapKeyFirstBlock)
        mapKeyBirth[entry.first] = locked_chain.getBlockTime(entry.second) - TIMESTAMP_WINDOW; 
}
/**
 * Compute smart timestamp for a transaction being added to the wallet.
 *
 * Logic:
 * - If sending a transaction, assign its timestamp to the current time.