Details here: https://docs.ansible.com/ansible/devel/porting_guides/porting_guide_6.html#id36
Basically:
```yaml
- name: Prior to 2.13
debug:
msg: '[1] + {{ [2] }}'
- name: 2.13 and forward
debug:
msg: '{{ [1] + [2] }}'
```
Interestingly, we had been using the new/safe syntax in lofs of places.
We were using the broken one in many others though. Hopefully all
instances were fixed by this patch.
The `to_nice_yaml` helper will by default wrap any string YAML values on
the first space after column 80. This can in worst case yield invalid
YAML syntax. More details in Ansible's documentation here:
https://docs.ansible.com/ansible/latest/user_guide/playbooks_filters.html#formatting-data-yaml-and-json
In short, you need to explicitly provide a custom width argument of a
high number of some kind to avoid the line wrapping.
Until now, we were leaving services "enabled"
(symlinks in /etc/systemd/system/multi-user.target.wants/).
We clean these up now. Broken symlinks may still exist in older
installations that enabled/disabled services. We're not taking care
to fix these up. It's just a cosmetic defect anyway.
