diff --git a/engines/plos_authors/Gemfile.lock b/engines/plos_authors/Gemfile.lock
index db40dcb53..c90a58c63 100644
--- a/engines/plos_authors/Gemfile.lock
+++ b/engines/plos_authors/Gemfile.lock
@@ -73,9 +73,9 @@ GEM
       activesupport (>= 3.0)
       sprockets (>= 2.8, < 4.0)
     thor (0.19.1)
-    thread_safe (0.3.4)
+    thread_safe (0.3.6)
     tilt (1.4.1)
-    tzinfo (1.2.2)
+    tzinfo (1.2.10)
       thread_safe (~> 0.1)
 
 PLATFORMS