Search in knowledge base not working

Technical assistance
1

After upgrading from 3.6 to 4, the search box in knowledge base is not working anymore. It always shows empty.
We had already an the same issue with the 422 error (Status Code 422 on tickets after update to newest Version 4) but this could be fixed with the provided answer.
Not sure what here the problem is.

Hopefully someone can help me out with this.

  • Used Zammad version: 4
  • Used Zammad installation type: repo
  • Operating system: ubuntu 18 LTS
  • Browser + version: firefox + chrome in newest version

Expected behavior:

Search should find answers

Actual behavior:

Search shows always empty

Steps to reproduce the behavior:

Try to use the search to find an knowledge base articel

2

Please read the release notes carefully:

The solution is hidden there within the technical requirements / breaking changes.

3

After trying the command, i got the message that we are on an old elastic search version (5.x) and this command is not supported. I have then upgraded it and then the command worked and also the search again.
The full command should be “zammad run rake searchindex:rebuild”

Hint: Upgrade first to version 6 and run the command and the upgrade to 7. When I went direct from 5 to 7, elastic failed to start