Hi, Chulai:
Sorry for this late reply. Only now I could notice you have posted this message reply.
I used Qt Linguist for doing the update. As to the lupate command line tool, I visited the page indicated by you, but couldn't find a link for downloading it. Please, provide it if possible, since also I have submitted the language file to further reviews for translation accuracy and typos correction.
I know absolete text shoud not present in new, updated language files, but I thought Qt Linguist took care of this somehow. Sorry.
As for translation update credits, where or to whom should I send them?
Thanks.
Regards.