most user friendly way would be to keep it alive for another 5 years.
If it is enough just to have transactional data, You could export all the needed tables to Excel, but then it could get complicated when users needs to find some additional details about specific transaction (like additional dimensions), and You will not be able to create printouts (like sales invoices) if it is needed.
I have seen only 1 company where exporting transactional data to excel was enough, others usually keep the system running, with only 1 or 2 users having access to it and providing needed information to other users upon request.
