From https://www.mediawiki.org/wiki/Manual_talk:MediaWiki_feature_list/Archive#User_IP_Address
"Is there an option to disable display of user's IP address? A privacy concern for me." And let me clarify: HIDE THE USERS IP ADDRESS means that "anonymous" would be shown instead of the users IP on the history page, recient changes page, etc. No, I am not looking for "$wgShowIPinHeader = false;". I want all edits to look the same except when users are logged in. How to do this?