Rename ->nid to ->id()
Change ->vid to ->getRevisionId()
Change ->created to getCreatedTime()
Change ->changed to getChangedTime()
Replace ->type with ->bundle()
Change ->title to label() or fix assignments
Converted node.html.twig files
Replace ->langcode with ->language()->langcode and similar.
Replace ->uid with getAuthor*()
Convert ->status to ->isPublished()
Convert ->sticky to ->isSticky()
Change ->promote to ->isPromoted