@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 
{
        WalletBalances result;
        result.balance = m_wallet.GetBalance();
        result.unconfirmed_balance = m_wallet.GetUnconfirmedBalance();
        result.immature_balance = m_wallet.GetImmatureBalance();
        result.have_watch_only = m_wallet.HaveWatchOnly();
        if (result.have_watch_only) {
            result.watch_only_balance = m_wallet.GetBalance(ISMINE_WATCH_ONLY);
            result.unconfirmed_watch_only_balance = m_wallet.GetUnconfirmedWatchOnlyBalance();
            result.immature_watch_only_balance = m_wallet.GetImmatureWatchOnlyBalance();
        }
        return result;
    }
    bool tryGetBalances(WalletBalances& balances, int& num_blocks) override