No environment variable dropping in QGIS 4.0

Afaics QGIS 4 is not meant to do a cleanup

Author: DelazJ

docs/server_manual/config.rst

@@ -178,7 +178,7 @@ several ways to define these variables. This is fully described in
         to server. If it's not there, check permissions.
 
         .. warning:: QGIS_SERVER_LOG_FILE is deprecated since QGIS 3.4, use QGIS_SERVER_LOG_STDERR instead.
-          File logging support will be removed in QGIS 4.0.
+          File logging support will be removed in QGIS 5.0.
 
      - ''
      - All