diff --git a/tests/tester/src/edition.rs b/tests/tester/src/edition.rs
index d0cbf1c55a..110169dd9b 100644
--- a/tests/tester/src/edition.rs
+++ b/tests/tester/src/edition.rs
@@ -115,20 +115,12 @@ static FEATURE_EDITION: phf::Map<&'static str, SpecEdition> = phf::phf_map! {
     // https://github.com/tc39/proposal-atomics-microwait
     "Atomics.pause" => SpecEdition::ESNext,
 
-    // Part of the next ES15 edition
-    "Atomics.waitAsync"  => SpecEdition::ESNext,
-    "regexp-v-flag" => SpecEdition::ESNext,
-    "String.prototype.isWellFormed" => SpecEdition::ESNext,
-    "String.prototype.toWellFormed" => SpecEdition::ESNext,
-    "resizable-arraybuffer" => SpecEdition::ESNext,
-    "promise-with-resolvers" => SpecEdition::ESNext,
-    "array-grouping" => SpecEdition::ESNext,
-    "set-methods" => SpecEdition::ESNext,
-
     // Standard language features
     "AggregateError" => SpecEdition::ES12,
+    "Atomics.waitAsync"  => SpecEdition::ES15,
     "align-detached-buffer-semantics-with-web-reality" => SpecEdition::ES12,
     "arbitrary-module-namespace-names" => SpecEdition::ES13,
+    "array-grouping" => SpecEdition::ES15,
     "ArrayBuffer" => SpecEdition::ES6,
     "array-find-from-last" => SpecEdition::ES14,
     "Array.prototype.at" => SpecEdition::ES13,
@@ -216,6 +208,7 @@ static FEATURE_EDITION: phf::Map<&'static str, SpecEdition> = phf::phf_map! {
     "Promise.any" => SpecEdition::ES12,
     "Promise.prototype.finally" => SpecEdition::ES9,
     "Proxy" => SpecEdition::ES6,
+    "promise-with-resolvers" => SpecEdition::ES15,
     "proxy-missing-checks" => SpecEdition::ES6,
     "Reflect" => SpecEdition::ES6,
     "Reflect.construct" => SpecEdition::ES6,
@@ -226,6 +219,8 @@ static FEATURE_EDITION: phf::Map<&'static str, SpecEdition> = phf::phf_map! {
     "regexp-match-indices" => SpecEdition::ES13,
     "regexp-named-groups" => SpecEdition::ES9,
     "regexp-unicode-property-escapes" => SpecEdition::ES9,
+    "regexp-v-flag" => SpecEdition::ES15,
+    "resizable-arraybuffer" => SpecEdition::ES15,
     "rest-parameters" => SpecEdition::ES6,
     "Set" => SpecEdition::ES6,
     "SharedArrayBuffer" => SpecEdition::ES8,
@@ -234,10 +229,13 @@ static FEATURE_EDITION: phf::Map<&'static str, SpecEdition> = phf::phf_map! {
     "String.prototype.at" => SpecEdition::ES13,
     "String.prototype.endsWith" => SpecEdition::ES6,
     "String.prototype.includes" => SpecEdition::ES6,
+    "String.prototype.isWellFormed" => SpecEdition::ES15,
     "String.prototype.matchAll" => SpecEdition::ES11,
     "String.prototype.replaceAll" => SpecEdition::ES12,
+    "String.prototype.toWellFormed" => SpecEdition::ES15,
     "String.prototype.trimEnd" => SpecEdition::ES10,
     "String.prototype.trimStart" => SpecEdition::ES10,
+    "set-methods" => SpecEdition::ES15,
     "super" => SpecEdition::ES6,
     "Symbol" => SpecEdition::ES6,
     "symbols-as-weakmap-keys" => SpecEdition::ES14,
@@ -335,6 +333,10 @@ pub(crate) enum SpecEdition {
     ///
     /// <https://262.ecma-international.org/14.0>
     ES14,
+    /// ECMAScript 15th Edition
+    ///
+    /// <https://262.ecma-international.org/15.0>
+    ES15,
     /// The edition being worked on right now.
     ///
     /// A draft is currently available [here](https://tc39.es/ecma262).
@@ -398,6 +400,7 @@ impl SpecEdition {
             Self::ES12,
             Self::ES13,
             Self::ES14,
+            Self::ES15,
             Self::ESNext,
         ]
         .into_iter()
diff --git a/tests/tester/src/main.rs b/tests/tester/src/main.rs
index 20876a309b..bc31822e35 100644
--- a/tests/tester/src/main.rs
+++ b/tests/tester/src/main.rs
@@ -606,6 +606,7 @@ struct VersionedStats {
     es12: Statistics,
     es13: Statistics,
     es14: Statistics,
+    es15: Statistics,
 }
 
 impl<'de> Deserialize<'de> for VersionedStats {
@@ -626,6 +627,8 @@ impl<'de> Deserialize<'de> for VersionedStats {
             es13: Statistics,
             #[serde(default)]
             es14: Option<Statistics>,
+            #[serde(default)]
+            es15: Option<Statistics>,
         }
 
         let inner = Inner::deserialize(deserializer)?;
@@ -641,8 +644,10 @@ impl<'de> Deserialize<'de> for VersionedStats {
             es12,
             es13,
             es14,
+            es15,
         } = inner;
         let es14 = es14.unwrap_or(es13);
+        let es15 = es15.unwrap_or(es14);
 
         Ok(Self {
             es5,
@@ -655,6 +660,7 @@ impl<'de> Deserialize<'de> for VersionedStats {
             es12,
             es13,
             es14,
+            es15,
         })
     }
 }
@@ -684,6 +690,7 @@ impl VersionedStats {
             SpecEdition::ES12 => self.es12,
             SpecEdition::ES13 => self.es13,
             SpecEdition::ES14 => self.es14,
+            SpecEdition::ES15 => self.es15,
             SpecEdition::ESNext => return None,
         };
         Some(stats)
@@ -703,6 +710,7 @@ impl VersionedStats {
             SpecEdition::ES12 => &mut self.es12,
             SpecEdition::ES13 => &mut self.es13,
             SpecEdition::ES14 => &mut self.es14,
+            SpecEdition::ES15 => &mut self.es15,
             SpecEdition::ESNext => return None,
         };
         Some(stats)
@@ -724,6 +732,7 @@ impl Add for VersionedStats {
             es12: self.es12 + rhs.es12,
             es13: self.es13 + rhs.es13,
             es14: self.es14 + rhs.es14,
+            es15: self.es15 + rhs.es15,
         }
     }
 }
@@ -740,6 +749,7 @@ impl AddAssign for VersionedStats {
         self.es12 += rhs.es12;
         self.es13 += rhs.es13;
         self.es14 += rhs.es14;
+        self.es15 += rhs.es15;
     }
 }