diff --git a/README.md b/README.md
index 6666430..47a78b0 100644
--- a/README.md
+++ b/README.md
@@ -14,7 +14,7 @@ Precise OpenStreetMap (OSM) map-matching for public transit schedules ([GTFS](ht
 ## Requirements
 
  * `cmake`
- * `gcc >= 4.9` (or `clang >= 5.0`)
+ * `gcc >= 4.9` (or `clang >= 3.9`)
 
 ## Building and Installation