@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 
break;
            }
            {
                auto locked_chain = chain().lock();
                Optional<int> tip_height = locked_chain->getHeight();
                if (!tip_height || *tip_height <= block_height || !locked_chain->getBlockHeight(block_hash)) {
                    
                    
                    break;
                }
                
                block_hash = locked_chain->getBlockHash(++*block_height);
                progress_current = chain().guessVerificationProgress(block_hash);
                
                const uint256 prev_tip_hash = tip_hash;
                tip_hash = locked_chain->getBlockHash(*tip_height);
                if (stop_block.IsNull() && prev_tip_hash != tip_hash) {
                    
                    progress_end = chain().guessVerificationProgress(tip_hash);
                }
            }
        }
        ShowProgress(strprintf("%s " + _("Rescanning..."), GetDisplayName()), 100); 
        if (block_height && fAbortRescan) {
            WalletLogPrintf("Rescan aborted at block %d. Progress=%f\n", block_height.get_value_or(0), progress_current);
            result.status = ScanResult::USER_ABORT;
        } else if (block_height && ShutdownRequested()) {
            WalletLogPrintf("Rescan interrupted by shutdown request at block %d. Progress=%f\n", block_height.get_value_or(0), progress_current);
            result.status = ScanResult::USER_ABORT;
        }