@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 
auto locked_chain = chain.lock();
    LOCK(walletInstance->cs_wallet);
    int rescan_height = 0;
    if (!gArgs.GetBoolArg("-rescan", false))
    {
        WalletBatch batch(*walletInstance->database);
        CBlockLocator locator;
        if (batch.ReadBestBlock(locator)) {
            if (const Optional<int> fork_height = locked_chain->findLocatorFork(locator)) {
                rescan_height = *fork_height;
            }
        }
    }
    const Optional<int> tip_height = locked_chain->getHeight();
    if (tip_height) {
        walletInstance->m_last_block_processed = locked_chain->getBlockHash(*tip_height);
    } else {
        walletInstance->m_last_block_processed.SetNull();
    }
    if (tip_height && *tip_height != rescan_height)
    {
        
        
        
        if (fPruneMode)
        {
            int block_height = *tip_height;
            while (block_height > 0 && locked_chain->haveBlockOnDisk(block_height - 1) && rescan_height != block_height) {
                --block_height;
            }