We migrated SISCON's management system off GeneXus in 15 calendar weeks and with 0 days of downtime. This article describes how the method is organized and why it works without stopping operations.
Module by module, not all at once
Each module goes through the same seven-phase cycle: discover, specify, migrate data, build, interface, verify and cut over. When it ends, the cycle starts again with the next module.
Three decisions that are yours
The business rule is signed off in the specification phase, parity is accepted in the verification phase and the cutover date is authorized by the client. Nothing moves forward without those sign-offs.
A single entry point
During the migration a single entry point splits traffic between the legacy and the new system. You can roll back at any time, which is why operations never stop.
AI agents, with a specification and review
Agents implement from a signed specification, each clause has its test and a person reviews the result. In our case that meant 581 API operations, 1,277 automated tests and 782 changes integrated with review.
The data
Data was migrated with its identifiers preserved, so references between records remain valid.