A lot of configuration properties have been renamed/replaced from Spring Boot 1.x to Spring Boot 2.0. So these changes must be incorporated in the application.yml/application.properties file to do a successful migration. To ease this process, Spring Boot has released the spring-boot-properties-migrator properties migrator, which can be used in the Maven configuration as follows:

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-properties-migrator</artifactId>
        <scope>runtime</scope>
</dependency>

When this dependency is used, it will analyze the application environment, print out any diagnostics at startup, and even temporarily migrate properties at runtime.