diff --git a/package.json b/package.json
index 8392fc0..940721b 100644
--- a/package.json
+++ b/package.json
@@ -133,7 +133,7 @@
     "dependencies": {
         "@apm-js-collab/code-transformer": "^0.18.1",
         "es-module-lexer": "^2.1.0",
-        "magic-string": "^0.30.21",
+        "magic-string": "^1.1.0",
         "module-details-from-path": "^1.0.4"
     },
     "devDependencies": {
diff --git a/src/rollup.ts b/src/rollup.ts
index 6c743c9..c46a9cf 100644
--- a/src/rollup.ts
+++ b/src/rollup.ts
@@ -6,7 +6,7 @@ import {
   shouldSkipCodeInjection,
   type CodeTransformerPluginOptions,
 } from "./core.js";
-import MagicString, { SourceMap } from "magic-string";
+import MagicString from "magic-string";
 
 export default function codeTransformerRollup(
   options: CodeTransformerPluginOptions,
@@ -27,7 +27,7 @@ export default function codeTransformerRollup(
     meta?: { magicString?: MagicString, chunks: unknown },
   ): {
     code: string;
-    map?: SourceMap;
+    map?: string;
   } | null => {
     if (!isJsFile(chunk.fileName)) {
       return null; // returning null means not modifying the chunk at all
@@ -74,10 +74,12 @@ export default function codeTransformerRollup(
 
     return {
       code: ms.toString(),
-      map: ms.generateMap({
-        file: chunk.fileName,
-        hires: "boundary" as unknown as undefined,
-      }),
+      map: ms
+        .generateMap({
+          file: chunk.fileName,
+          hires: "boundary" as unknown as undefined,
+        })
+        .toString(),
     };
   };
 
diff --git a/yarn.lock b/yarn.lock
index 77ebf4f..9b0b1a5 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1009,6 +1009,13 @@ magic-string@^0.30.21:
   dependencies:
     "@jridgewell/sourcemap-codec" "^1.5.5"
 
+magic-string@^1.1.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/magic-string/-/magic-string-1.1.0.tgz#54a8470aabf2a04b970177f26c0308cabea74a3f"
+  integrity sha512-kS3VHe0nEPST2saQV4Rbkchcd3UBRkVTQHo1D3h/ZTwFDhai/mfKkmtPAtD129EOI7K3HlHIsFOt0WrI2/oU9g==
+  dependencies:
+    "@jridgewell/sourcemap-codec" "^1.5.5"
+
 merge-stream@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/merge-stream/-/merge-stream-2.0.0.tgz#52823629a14dd00c9770fb6ad47dc6310f2c1f60"