You need to include a separate actuators module to enable them. IIRC in Spring Boot version 1.5 and older actuators were enabled and exposed as web endpoints by default. The heapdump endpoint mentioned in the article also required inclusion of Spring MVC module – which I guess most web apps do include.

In Spring Boot 2.0 and newer actuator module only exposes "info" and "health" web endpoints by default. Default configuration does expose more endpoints via JMX, though. Also, if your project includes Spring Security module actuator endpoints are secured by default.