Backward compatibility: (v6.0)

1) Versioning & backward compatibility

Since version 2, the pac4j project has adopted the semver versioning, to make things clearer.

Given a version X.Y.Z:

• when X changes, it’s a major version with breaking changes (example: 2.x, 3.x, and so on)
• when Y changes, it’s a minor version with no compilation/runtime breaking changes (for example, you can upgrade from 2.5.2 to 2.7.0 without any worry)
• when Z changes, it’s a bug fix(es) version with no compilation/runtime breaking change (no upgrade issue either).

Generally, pac4j implementations follow the semver versioning as well.

Notice that, while pac4j-* modules are backward compatible, you should always add the pac4j-javaee or pac4j-jakartaee or pac4j-core dependency in the same version as the upgraded pac4j-* dependency.

2) Maintenance

a) Core project

Community efforts are focused on the latest stream (the master branch).

For older streams, contributions may be accepted and bug/security fixes may be backported.

b) Implementations

The “major” implementations are:

• jee-pac4j
• buji-pac4j
• spring-webmvc-pac4j
• spring-security-pac4j
• play-pac4j
• CAS

They should be upgraded to the latest pac4j stream.