There are three types of migrations: Standard EF Migration - These are required when a model change needs to occur since the code is tightly coupled to the database change. For this type, you must reserve the developer migration token to let other developers know you are about to make a model/db change. Migration Rollups (in Asana) or Data Migrations - Any data migration that does not have to be closely coordinated with a corresponding code/class change can be put into the Migration Rollups project under a v.X.Y.Z section for the branch in question. (We put them in Asana in order to reduce the size of the Rock.Migrations.dll since each EF migration causes it to grow larger.)Hotfix Migrations (Rock/Plugin/HotFixes/*) - These are very similar to the Migration Rollups type since they do not have to be closely coordinated with a corresponding code/class change, but they are going into a release of Rock that is earlier than where the EF code migration token is currently located. Like standard EF migrations, they are also ordered (example: [MigrationNumber( 145, ... )]). Note: We often just put these migrations into the the Migration Rollups project to avoid needing to coordinate the hotfix version number with other developers. In that case, they will be collected from Asana and put into a HotFix migration when the hotfix release is being packaged for the alpha testing phase. Subpages describe each of these in further detail.