Is there any tutorial available for the latest “outsourced” custom actions in 0.11.1? Is it possible in 0.11.1 to use the older custom action format (without using rasa_core_sdk)? Also, I want to know more about the online training using restful APIs and NLG. Couldn’t find any guide/documentation about the latest online training changes and NLG.
No, you have to run the action server now, but detailed information on how to do it with python actions is written here: http://rasa.com/docs/core/customactions/
As for online training, you can take a look at how it’s implemented now here: https://github.com/RasaHQ/rasa_core/blob/master/rasa_core/training/online.py
I think such major changes shouod be posted somewhere explicity like here Important Updates. I am now surprised about this change for custom actions? What is the reason for this and what can I do now better maybe?
So online training is also now running as a server too? So you can link it to a GUI. Is there maybe such an interface out there already?
It was mentioned in the CHANGELOG in the repository, but I agree that such groundbreaking changes should be announced everywhere on a larger scale.
As for online training, it’s just 2 days old and it doesn’t even have a documentation yet, let alone a GUI interface. People would’ve started working on it (as have I), so expect a crude GUI within 5-10 days.
We linked to the migration guide from Important Updates 
This is something you should always read when updating to a major version. The reason for this is that you can now replace parts of your setup easier, e.g. if you want to change a custom action, you can just restart the action server rather than the whole core server.
Online training is run via http yes, but the concept has existed for a while now, just the http part is new. As for an interface, this isn’t something we’re focusing on right now, but of course anything that comes from the community is great!