Youzhou (894) — the same event in Old Book of Tang and New Book of Tang

Old Book of Tang: Li Keyong took Youzhou and appointed Liu Rengong as Youhou.; New Book of Tang: Li Keyong captured Youzhou.

What each source says

Li Keyong took Youzhou and appointed Liu Rengong as Youhou.

克用陷幽州，以李匡威故將劉仁恭為幽州兵為留後。
Location: 舊唐書卷20上乾寧1年 12月

Li Keyong captured Youzhou.

丙辰，李克用陷幽州
Location: 新唐書卷010 昭宗·哀帝乾寧1年12月

Place: 幽州