diff --git a/ablescript/src/base_55.rs b/ablescript/src/base_55.rs
index ea1255d..2e5a5a3 100644
--- a/ablescript/src/base_55.rs
+++ b/ablescript/src/base_55.rs
@@ -5,7 +5,7 @@ pub const fn char2num(c: char) -> isize {
         '/' => 53,
         '\\' => 54,
         '.' => 55,
-        'U' => -210,
+        'U' => -210, // Backwards compatibility
         'A'..='Z' => -(c as isize) + 64,
         'a'..='z' => (c as isize) - 96,
         _ => 0,