diff --git a/autoload/airline/highlighter.vim b/autoload/airline/highlighter.vim
index ed417d64..4759da8d 100644
--- a/autoload/airline/highlighter.vim
+++ b/autoload/airline/highlighter.vim
@@ -6,7 +6,7 @@ scriptencoding utf-8
 let s:is_win32term = (has('win32') || has('win64')) &&
                    \ !has('gui_running') &&
                    \ (empty($CONEMUBUILD) || &term !=? 'xterm') &&
-                   \ empty($WTSESSION) &&
+                   \ empty($WT_SESSION) &&
                    \ !(exists("+termguicolors") && &termguicolors)
 
 let s:separators = {}