We have a topic already open for this with the GoJara plugin. Please see here Gojara and Spark Client.
I am hoping that one of the developers of Spark sees this. Is the updated client compatible with GoJara or not?
We tested with Gajim and we see the ability to register to third party services there.
@guus am I correct in assuming that you are among the developers of the Spark client?
I thank you in advance.