On 4.5.0.16 (January) we fixed the issue of “Manual MMS download is broken” which turned out to be a sandboxing error: the Messages app was lacking the MmsEngine permission. This Jolla bug was linked to [4.3.0.12] MMS works, but MMS retry fails, stays Waiting forever
Then there was another Jolla bug, “When receiving MMS, ‘Problem with downloading MMS’ is shown”, reported originally in this post which was linked to the Jolla bug. One of our developers was able to reproduce the issue while travelling in Lithuania. He was getting an “mms-task-http] HTTP status 7 (Connection terminated unexpectedly)”.
However, after upgrading to 4.5.0.16, the problem vanished and he was able to receive MMS messages.
From this, we concluded that the problem with downloading MMS was fixed.
But I failed to see that the problem in sending MMS was bundled into this same post. There was no particular fix for outbound messages. It would be best to make a new report on the remaining/current MMS problems here, using the OS release 4.5.0.19.