diff --git a/package-lock.json b/package-lock.json
index 3367741..c84a251 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -9,7 +9,7 @@
       "version": "0.0.0-dev",
       "license": "MIT",
       "dependencies": {
-        "@croct/json": "^1.0.0"
+        "@croct/json": "^1.1"
       },
       "devDependencies": {
         "@croct/eslint-plugin": "^0.6.0",
diff --git a/package.json b/package.json
index 0cc9a69..ed561af 100644
--- a/package.json
+++ b/package.json
@@ -44,6 +44,6 @@
     "**/*.ts"
   ],
   "dependencies": {
-    "@croct/json": "^1.0.0"
+    "@croct/json": "^1.1"
   }
 }
diff --git a/src/logger.ts b/src/logger.ts
index 7184b0f..5eb6ffe 100644
--- a/src/logger.ts
+++ b/src/logger.ts
@@ -1,9 +1,9 @@
-import {JsonCompatibleObject} from '@croct/json';
+import {ReadonlyJsonCompatibleObject} from '@croct/json';
 
 /**
  * Additional information about the log message.
  */
-export type LogDetails = JsonCompatibleObject;
+export type LogDetails = ReadonlyJsonCompatibleObject;
 
 /**
  * The severity of the log message.
@@ -48,7 +48,7 @@ export type Log<D extends LogDetails = LogDetails> = {
      * The log message.
      */
     message: string,
-} & (JsonCompatibleObject extends D ? {details?: D} : {details: D});
+} & (LogDetails extends D ? {details?: D} : {details: D});
 
 /**
  * A common interface for loggers.