diff --git a/build.gradle b/build.gradle
index 0fc2239..6b12864 100644
--- a/build.gradle
+++ b/build.gradle
@@ -26,7 +26,7 @@ ext {
     junit_version = "4.12"
     threetenbp_version = "1.3.5"
     json_fire_version = "1.8.0"
-    slf4j_core_version = "1.2.3"
+    slf4j_core_version = "1.6.3"
     slf4j_classic_version = "1.2.3"
     slf4j_version = "1.7.30"
 }