diff --git a/Configurations.md b/Configurations.md
index 1df79daf798..0f4320853fe 100644
--- a/Configurations.md
+++ b/Configurations.md
@@ -1257,7 +1257,7 @@ Control the case of the letters in hexadecimal literal values
 
 - **Default value**: `Preserve`
 - **Possible values**: `Preserve`, `Upper`, `Lower`
-- **Stable**: No (tracking issue: [#5081](https://github.com/rust-lang/rustfmt/issues/5081))
+- **Stable**: Yes
 
 ## `float_literal_trailing_zero`
 
diff --git a/src/config/mod.rs b/src/config/mod.rs
index 8abb7439257..8c4ed07c3d7 100644
--- a/src/config/mod.rs
+++ b/src/config/mod.rs
@@ -78,7 +78,7 @@ create_config! {
         "Format the bodies of declarative macro definitions";
     skip_macro_invocations: SkipMacroInvocations, false,
         "Skip formatting the bodies of macros invoked with the following names.";
-    hex_literal_case: HexLiteralCaseConfig, false, "Format hexadecimal integer literals";
+    hex_literal_case: HexLiteralCaseConfig, true, "Format hexadecimal integer literals";
     float_literal_trailing_zero: FloatLiteralTrailingZeroConfig, false,
         "Add or remove trailing zero in floating-point literals";
 
diff --git a/tests/source/configs/hex_literal_case/hex_literal_lower.rs b/tests/source/configs/hex_literal_case/hex_literal_lower.rs
new file mode 100644
index 00000000000..de2c9f9d9dc
--- /dev/null
+++ b/tests/source/configs/hex_literal_case/hex_literal_lower.rs
@@ -0,0 +1,9 @@
+// rustfmt-hex_literal_case: Lower
+fn main() {
+    let h1 = 0xCAFE_5EA7;
+    let h2 = 0xCAFE_F00Du32;
+    let h3 = -0xCAFE_5EA7;
+    let h4 = -0xCAFE_F00Di32;
+    let h5 = 0xABcD07_i32;
+    let h6 = -0xABcD07_i32;
+}
diff --git a/tests/source/configs/hex_literal_case/hex_literal_preserve.rs b/tests/source/configs/hex_literal_case/hex_literal_preserve.rs
new file mode 100644
index 00000000000..876592a4f64
--- /dev/null
+++ b/tests/source/configs/hex_literal_case/hex_literal_preserve.rs
@@ -0,0 +1,9 @@
+// rustfmt-hex_literal_case: Preserve
+fn main() {
+    let h1 = 0xcAfE_5Ea7;
+    let h2 = 0xCaFe_F00du32;
+    let h3 = -0xcAfE_5Ea7;
+    let h4 = -0xCaFe_F00di32;
+    let h5 = 0xAbcd07_i32;
+    let h6 = -0xAbcd07_i32;
+}
diff --git a/tests/source/configs/hex_literal_case/hex_literal_upper.rs b/tests/source/configs/hex_literal_case/hex_literal_upper.rs
new file mode 100644
index 00000000000..d3fbe367185
--- /dev/null
+++ b/tests/source/configs/hex_literal_case/hex_literal_upper.rs
@@ -0,0 +1,9 @@
+// rustfmt-hex_literal_case: Upper
+fn main() {
+    let h1 = 0xCaFE_5ea7;
+    let h2 = 0xCAFE_F00Du32;
+    let h3 = -0xCaFE_5ea7;
+    let h4 = -0xCAFE_F00Di32;
+    let h5 = 0xAbcd07_i32;
+    let h6 = -0xAbcd07_i32;
+}
diff --git a/tests/source/hex_literal_lower.rs b/tests/source/hex_literal_lower.rs
deleted file mode 100644
index ce307b3aa52..00000000000
--- a/tests/source/hex_literal_lower.rs
+++ /dev/null
@@ -1,5 +0,0 @@
-// rustfmt-hex_literal_case: Lower
-fn main() {
-    let h1 = 0xCAFE_5EA7;
-    let h2 = 0xCAFE_F00Du32;
-}
diff --git a/tests/source/hex_literal_upper.rs b/tests/source/hex_literal_upper.rs
deleted file mode 100644
index b1092ad71ba..00000000000
--- a/tests/source/hex_literal_upper.rs
+++ /dev/null
@@ -1,5 +0,0 @@
-// rustfmt-hex_literal_case: Upper
-fn main() {
-    let h1 = 0xCaFE_5ea7;
-    let h2 = 0xCAFE_F00Du32;
-}
diff --git a/tests/target/configs/hex_literal_case/hex_literal_lower.rs b/tests/target/configs/hex_literal_case/hex_literal_lower.rs
new file mode 100644
index 00000000000..d1d284c6df0
--- /dev/null
+++ b/tests/target/configs/hex_literal_case/hex_literal_lower.rs
@@ -0,0 +1,9 @@
+// rustfmt-hex_literal_case: Lower
+fn main() {
+    let h1 = 0xcafe_5ea7;
+    let h2 = 0xcafe_f00du32;
+    let h3 = -0xcafe_5ea7;
+    let h4 = -0xcafe_f00di32;
+    let h5 = 0xabcd07_i32;
+    let h6 = -0xabcd07_i32;
+}
diff --git a/tests/target/configs/hex_literal_case/hex_literal_preserve.rs b/tests/target/configs/hex_literal_case/hex_literal_preserve.rs
new file mode 100644
index 00000000000..876592a4f64
--- /dev/null
+++ b/tests/target/configs/hex_literal_case/hex_literal_preserve.rs
@@ -0,0 +1,9 @@
+// rustfmt-hex_literal_case: Preserve
+fn main() {
+    let h1 = 0xcAfE_5Ea7;
+    let h2 = 0xCaFe_F00du32;
+    let h3 = -0xcAfE_5Ea7;
+    let h4 = -0xCaFe_F00di32;
+    let h5 = 0xAbcd07_i32;
+    let h6 = -0xAbcd07_i32;
+}
diff --git a/tests/target/configs/hex_literal_case/hex_literal_upper.rs b/tests/target/configs/hex_literal_case/hex_literal_upper.rs
new file mode 100644
index 00000000000..4336453abae
--- /dev/null
+++ b/tests/target/configs/hex_literal_case/hex_literal_upper.rs
@@ -0,0 +1,9 @@
+// rustfmt-hex_literal_case: Upper
+fn main() {
+    let h1 = 0xCAFE_5EA7;
+    let h2 = 0xCAFE_F00Du32;
+    let h3 = -0xCAFE_5EA7;
+    let h4 = -0xCAFE_F00Di32;
+    let h5 = 0xABCD07_i32;
+    let h6 = -0xABCD07_i32;
+}
diff --git a/tests/target/hex_literal_lower.rs b/tests/target/hex_literal_lower.rs
deleted file mode 100644
index 5c27fded167..00000000000
--- a/tests/target/hex_literal_lower.rs
+++ /dev/null
@@ -1,5 +0,0 @@
-// rustfmt-hex_literal_case: Lower
-fn main() {
-    let h1 = 0xcafe_5ea7;
-    let h2 = 0xcafe_f00du32;
-}
diff --git a/tests/target/hex_literal_preserve.rs b/tests/target/hex_literal_preserve.rs
deleted file mode 100644
index e8774d0bb24..00000000000
--- a/tests/target/hex_literal_preserve.rs
+++ /dev/null
@@ -1,5 +0,0 @@
-// rustfmt-hex_literal_case: Preserve
-fn main() {
-    let h1 = 0xcAfE_5Ea7;
-    let h2 = 0xCaFe_F00du32;
-}
diff --git a/tests/target/hex_literal_upper.rs b/tests/target/hex_literal_upper.rs
deleted file mode 100644
index 48bb93d2c1c..00000000000
--- a/tests/target/hex_literal_upper.rs
+++ /dev/null
@@ -1,5 +0,0 @@
-// rustfmt-hex_literal_case: Upper
-fn main() {
-    let h1 = 0xCAFE_5EA7;
-    let h2 = 0xCAFE_F00Du32;
-}