Reading the Drupal Changes records I found that drupal_get_message() and drupal_set_message() replaced by Messenger service so lets suppose that I have a module that use the
drupal_get_message() function and I want to replace it with the new Messenger service. If I do it my module only will works starting from Drupal Core >= 8.5.
So, in this point what is the correct way to produce the next module release?
Should I restrict the next release to a specific Core version adding a comment in the release notes or should I create a new branch (lets says 8.x-2.x) to implement this changes and have two module versions like 8.x-1.x (working for Core < 8.5) and 8.x-2.x (working for Core >= 8.5)?