@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 
fsbridge::ofstream file;
    file.open(filepath);
    if (!file.is_open())
        throw JSONRPCError(RPC_INVALID_PARAMETER, "Cannot open wallet dump file");
    std::map<CTxDestination, int64_t> mapKeyBirth;
    const std::map<CKeyID, int64_t>& mapKeyPool = pwallet->GetAllReserveKeys();
    pwallet->GetKeyBirthTimes(*locked_chain, mapKeyBirth);
    std::set<CScriptID> scripts = pwallet->GetCScripts();
    
    
    std::vector<std::pair<int64_t, CKeyID> > vKeyBirth;
    for (const auto& entry : mapKeyBirth) {
        if (const CKeyID* keyID = boost::get<CKeyID>(&entry.first)) { 
            vKeyBirth.push_back(std::make_pair(entry.second, *keyID));
        }
    }
    mapKeyBirth.clear();
    std::sort(vKeyBirth.begin(), vKeyBirth.end());
    
    file << strprintf("# Wallet dump created by Bitcoin %s\n", CLIENT_BUILD);
    file << strprintf("# * Created on %s\n", FormatISO8601DateTime(GetTime()));
    const Optional<int> tip_height = locked_chain->getHeight();
    file << strprintf("# * Best block at time of backup was %i (%s),\n", tip_height.get_value_or(-1), tip_height ? locked_chain->getBlockHash(*tip_height).ToString() : "(missing block hash)");
    file << strprintf("#   mined on %s\n", tip_height ? FormatISO8601DateTime(locked_chain->getBlockTime(*tip_height)) : "(missing block time)");
    file << "\n";
    
    CKeyID seed_id = pwallet->GetHDChain().seed_id;
    if (!seed_id.IsNull())
    {
        CKey seed;