Looks good and nice logo 🙂 Is there a guide for updating "old" Duct applications to the new one? What to take into account?
There isn't currently a guide, but I'll add it to my todo list to write one. In a nutshell there are two main changes:
1. Duct now uses tools.deps instead of Leiningen.
2. Modules no longer change the config directly, but instead produce maps that are merged into the config.
Due to the second change a lot of the modules have different configuration syntax, so converting to the newer version of Duct essentially means updating the module configs and moving the configuration into duct.edn.
How to do this is a little more complex than is possible to address in a slack reply, as you'll need to treat each module on a case-by-case basis.
Is it also mandatory to convert the duct_hierarchy.edn file to to integrant/hierarchy.edn?
Yes, as that functionality was moved into Integrant. They're the same syntax, just in a different location.