diff --git a/requirements.txt b/requirements.txt
index 472bbff19..d9f9cbf29 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -21,7 +21,7 @@ joserfc==1.7.0
 email-validator==2.3.0
 watchdog==6.0.0
 zstandard==0.25.0
-platformdirs>=2.4.0,<3  # platformdirs >=3 conflicts when building Debian packages
+platformdirs>=2.4.0  # fastmcp-slim >=3.4 requires >=4.0.0; upper bound removed for compatibility
 truststore>=0.10.4; python_version >= '3.10'
 
 # Shared dependencies (also used by AI Copilot)