When a new project version is introduced, a project conversion should be made. In the Axon.ivy Designer the project is marked with an error, there you can right-click on the project and use Convert to convert the project. We distinguish between optional and necessary project conversion. Optional project conversions lead to the fact that already deployed projects continue to run without a conversion. If a project migration is necessary, the projects must first be converted in the Axon.ivy Designer and then newly deployed.
Migrating an Engine usually implies a conversion of the system database. This can be resolved automatically by invoking the System Database Conversion.
If the Engine is integrated with a reverse proxy (e.g. IIS or Apache), it is best practice to check if the most recent Apache Tomcat Connector is installed. For further information look at Upgrade Apache Tomcat Connector.