Axon 2.x to 3.x porting guide

I’d like to move from Axon 2.4.3 to something closer to 3.0. Is there a document that explains what needs to be done given the current state of either 3.0-M2 or master?


Hi Joseph,

documentation is (very high) on our backlog. We will also include (or create a separate) migration guide.
Axon 3 is currently in m2 status. Once we get to a proper release candidate, it will include the documentation.

Kind regards,


Thanks. Is there anything that a new user of Axon can help with on these tasks?

Hi Joseph,

that depends on how new you are, and how far in the deep end you’re comfortable jumping.

If you’re willing to help on porting the sample application to Axon 3, that’d be great.
Basically what needs to happen is the following:

  • update maven dependencies to 3.0-M2
  • change aggregates extending AbstractAnnotatedAggregateRoot. Remove extends and statically import the apply method from AggregateLifyCycle.
  • Same for AbstractAnnotatedSaga (import lifecycle methods from SagaLiceCycle)
  • Replace Spring XML support by Spring JavaConfig
  • Define SubscribingEventProcessors for the various components and register the event handlers with them.

The last bullet is probably a bit hard without documentation, but the other should be reasonably ‘doable’.

Let me know if you’re willing/able to pick any of these tasks…



Any news on the migration guide?


the reference guide is up first. When the 3.0 GA release is out, we’ll start working on a migration guide.



When the 3.0 GA release is out, we’ll start working on a migration guide.

so last weekend I attempted to upgrade a toy project I have in Axon 2 to Axon 3…
After upgrading the version in my pom.xml, I was greeted with numerous compile time errors :slight_smile:

A couple of packages were gone (org.axonframework.unitofwork, import org.axonframework.commandhandling.annotation, org.axonframework.repository no name a few…)
…more classes than I could count have also disappeared…

Without nowhere to start making sense of what needs to change, I abandoned the idea to upgrade and went out for a walk instead :slight_smile:

A migration guide would be really really useful! :slight_smile:

Hi Dadepo,

Definitely got a point there…I’ll see what we can do to work on this ASAP.
Thanks for the refresher btw!
If you’ve got time it would be great of you could share some pitfalls you’ve come across.



refresher :slight_smile:

My current thinking is that we’ll skip 3.0 and jump straight to 3.1. Will the migration guide be part of the 3.1 release ? I appreciate that it’s potentially quite a daunting task :confused: