Complete shift from in-office IBM AS/400 ERP to Magento eCommerce, with embedded ERP. All business processes were re-build within Magento to do migration. Today every order is online order, and now there is way to start using all the data collected through the years.
Also Magento allows business to evolve.
Multi-process Optimized Upgrade Replay from Magento 1.5 (1.10 EE) and lower to 1.6 (1.11 EE) and higher. In order to run optimized replay you need to run original upgrade in database with same structure. Replay script uses pdo_mysql.log to read queries and estimate execution time.
#Real life results:
1.9 EE -> 1.11 EE ==> Original upgrade ~34 hours vs Optimized Replay 4 hours
1.4 CE -> 1.12 EE ==> Original upgrade ~15 hours vs Optimized Replay 2 hours