To edit the date of publication and other details, see "How do I edit my research item's details?" in https://help.researchgate.net/hc/en-us/articles/14293081125777-Reviewing-editing-and-featuring-your-research for instructions.
Please note that many journals are missing in ResearchGate's database (see https://explore.researchgate.net/display/support/Journals for explanations). See my reply to this similar question for a recommendation what to do in such a case: https://www.researchgate.net/post/How_can_I_add_the_name_of_the_journal_where_my_article_is_published_when_the_name_of_the_journal_is_automatically_cancelled