diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4e5accfa..5852fe0e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,7 +2,7 @@
 
 ## 2.1.2 under development
 
-- no changes in this release.
+- Chg #126: Add `ext-psr` to `conflict` section in `composer.json` (@samdark)
 
 ## 2.1.1 June 03, 2025
 
diff --git a/composer.json b/composer.json
index 2753f7e0..a374d16a 100644
--- a/composer.json
+++ b/composer.json
@@ -51,6 +51,9 @@
         "yiisoft/log-target-file": "Allows writing log messages to the files",
         "yiisoft/log-target-syslog": "Allows writing log messages to the Syslog"
     },
+    "conflict": {
+        "ext-psr": "*"
+    },
     "autoload": {
         "psr-4": {
             "Yiisoft\\Log\\": "src"