diff --git a/Gemfile.lock b/Gemfile.lock
index 7e1fb93..c96fabe 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -4,8 +4,8 @@ GEM
     addressable (2.5.2)
       public_suffix (>= 2.0.2, < 4.0)
     colorator (1.1.0)
-    ffi (1.9.18)
-    ffi (1.9.18-x86-mingw32)
+    ffi (1.15.5)
+    ffi (1.15.5-x86-mingw32)
     forwardable-extended (2.6.0)
     jekyll (3.6.2)
       addressable (~> 2.4)