diff --git a/lib/reline/unicode/east_asian_width.rb b/lib/reline/unicode/east_asian_width.rb
index 97dfec4c52..ce7f7f2645 100644
--- a/lib/reline/unicode/east_asian_width.rb
+++ b/lib/reline/unicode/east_asian_width.rb
@@ -1,6 +1,7 @@
 class Reline::Unicode::EastAsianWidth
   # This is based on EastAsianWidth.txt
   # EastAsianWidth.txt
+  # UNICODE_VERSION = '15.0.0'
 
   # Fullwidth
   TYPE_F = /^[#{ %W(