Helpful resources:
Property migrator: org.springframework.boot:spring-boot-properties-migrator
Flyway Release Notes: https://flywaydb.org/documentation/releaseNotes#5.0.0
OAuth 2 Spring Security FAQ: https://github.com/spring-projects/spring-security/wiki/OAuth-2.0-Features-Matrix
Password Migration: http://info.michael-simons.eu/2018/01/13/spring-security-5-new-password-storage-format/
Actuator Documentation: https://docs.spring.io/spring-boot/docs/current/actuator-api/html/
und https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-2.0-Migration-Guide#spring-boot-actuator
Spring Boot Buch: http://springbootbuch.de