MicroProfile Metrics 2.0
To use this version in your code, include the following in your Maven pom:
<dependency>
<groupId>org.eclipse.microprofile.metrics</groupId>
<artifactId>microprofile-metrics-api</artifactId>
<version>2.0</version>
</dependency>
For changes consult the changelog.html file, which also clearly indicates the breaking changes.
The changelog is also part of the spec documents.