The second possible strategy is a big-bang migration. At some point, the old tool is switched off, all data is migrated to the new tool, and the new tool is made available. If there is anything that does not breathe DevOps, it is such a migration. It has a high potential for issues and often there is no turning back. Often, this is not a good migration strategy.

However, one situation where such an approach might make sense is the migration of source control. There are tools available for migrating from different sources to any type of hosted Git solution, including Azure DevOps. Source control also has the benefit that change history is built so deep into the system that migrating with history is often easier than for other types of data.