@ anja
Sorry, to hear you lost your translations… my guess is that the CodeStyling Localization plugin placed your translation in the Connections plugin folder. When WordPress does updates, it deletes the folder, so there nothing I can do about that. I do have an alternate folder where custom translations can be save to so they are update safe. The instructions can be found on the translations doc page in the FAQ on where to save to MO/PO files.
re: What is the next step?
I do not see that you requested to be part of a translation team (a language) you need to do that in Transifex or let me know which language you would like to help translate. After you are added to the team, you’ll be able to help translate.
re: And understanding your explanation correctly, the words I might translate now, will only be published within the next update. So in the meanwhile should I do the manual way again with po/mo files?
No, you do not need to wait for an update, the instructions to use the updated translation is in the I’ve added or updated a translation, do I have to wait for an update? FAQ on the translations doc page.
Hope that helps!