Non-static method OC_App::enable() should not be called statically at /appinfo/app.php#27

[solracsf]

{
  "reqId":"GaplJEwNQpJlCxC9MWyD",
  "level":3,
  "time":"2020-11-09T11:53:54+01:00",
  "app":"PHP",
  "method":"GET",
  "url":"/apps/files/",
  "message":{
    "Exception":"Error",
    "Message":"Non-static method OC_App::enable() should not be called statically at /apps/files_external_dropbox/appinfo/app.php#27",
    "Code":0,
    "Trace":[
      {
        "file":"/apps/files_external_dropbox/appinfo/app.php",
        "line":27,
        "function":"onError",
        "class":"OC\\Log\\ErrorHandler",
        "type":"::"
      },
      {
        "file":"/lib/private/legacy/OC_App.php",
        "line":266,
        "args":[
          "/apps/files_external_dropbox/appinfo/app.php"
        ],
        "function":"require_once"
      },
      {
        "file":"/lib/private/legacy/OC_App.php",
        "line":155,
        "function":"requireAppFile",
        "class":"OC_App",
        "type":"::"
      },
      {
        "file":"/lib/private/legacy/OC_App.php",
        "line":128,
        "function":"loadApp",
        "class":"OC_App",
        "type":"::"
      },
      {
        "file":"/lib/base.php",
        "line":996,
        "function":"loadApps",
        "class":"OC_App",
        "type":"::"
      },
      {
        "file":"/index.php",
        "line":37,
        "function":"handleRequest",
        "class":"OC",
        "type":"::"
      }
    ],
    "File":"/lib/private/Log/ErrorHandler.php",
    "Line":91,
    "CustomMessage":"--"
  },
  "userAgent":"Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:60.0) Gecko/20100101 Firefox/60.0",
  "version":"19.0.4.2"
}