Here you'll find the configurable properties of our reusable CELUM Connectors. In contrast to the extensions that run inside CELUM, connectors run in some 3rd-party system and connect to CELUM from the outside via an API. So the two systems must be able to communicate between one another in order for this to work.
6.20 (aka 25.1) contains a lot of breaking changes due to dependency updates, so for the first time in a long time you probably won't be able to simply deploy extensions designed for previous versions. When in doubt, ask us!