What is the difference between Apache Karaf 2 and 3?

Question

What is the difference between Apache Karaf 2 and 3? They are both listed in the release schedule, and there are download pages for both, so they're both maintained. It's not mentioned in the Karaf FAQ, and Google doesn't have anything on the subject either.

I did notice that the consoles are pretty different.

Also, when should I use which version?

Answer 1

Well it's mostly the underlying dependencies that differ and the amount of specialties. Karaf 2.3 as still maintained is stable and proven to work. Karaf 3.0 is having newer dependencies and brings support for more features and new commands (like creating a JDBC datasource) Main difference, Karaf 2.3 supports OSGi R4.3 while Karaf 3 supports R4.3 with partial R5 support. Karaf 4.0 will be supporting R5 fully.

Take a look at these two links to see the differences in supported versions:
Karaf 2.3
Karaf 3.0

For a complete list of changes, take a look at the Jira-Issues (Changeset) or this Road-Map.