diff --git a/draft-marchan-kdl2.md b/draft-marchan-kdl2.md
index 008b9a5..d16295e 100644
--- a/draft-marchan-kdl2.md
+++ b/draft-marchan-kdl2.md
@@ -983,10 +983,8 @@ string-character :=
     [^\\"] - disallowed-literal-code-points
 ws-escape := '\\' (unicode-space | newline)+
 hex-digit := [0-9a-fA-F]
-hex-unicode := hex-digit{1, 6} - surrogates
-surrogates := [dD][8-9a-fA-F]hex-digit{2}
-// U+D800-DFFF: D  8         00
-//              D  F         FF
+hex-unicode := [\u{0}-\u{10FFFF}] - surrogate  // Unicode Scalar Value₁₆
+surrogate := [\u{D800}-\u{DFFF}]
 
 raw-string := '#' raw-string-quotes '#' | '#' raw-string '#'
 raw-string-quotes :=
diff --git a/tests/test_cases/input/unicode_escaped_above_max_fail.kdl b/tests/test_cases/input/unicode_escaped_above_max_fail.kdl
new file mode 100644
index 0000000..5db8765
--- /dev/null
+++ b/tests/test_cases/input/unicode_escaped_above_max_fail.kdl
@@ -0,0 +1 @@
+no "Higher than max Unicode Scalar Value \u{10FFFF} \u{11FFFF}"
diff --git a/tests/test_cases/input/unicode_escaped_noncanon_fail.kdl b/tests/test_cases/input/unicode_escaped_noncanon_fail.kdl
new file mode 100644
index 0000000..409fac7
--- /dev/null
+++ b/tests/test_cases/input/unicode_escaped_noncanon_fail.kdl
@@ -0,0 +1 @@
+no "Non-canonical format for Unicode Scalar Value with extra 0s: \u{00FFFF} instead of \u{FFFF}"