diff --git a/Gemfile.lock b/Gemfile.lock
index fda0668..bac759d 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -205,10 +205,16 @@ GEM
     mime-types (3.3.1)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2020.1104)
-    mimemagic (0.3.5)
+    mimemagic (0.4.3)
+      nokogiri (~> 1)
+      rake
+    mini_portile2 (2.5.1)
     mn2pdf (1.25)
     mn2sts (1.5.0)
     multipart-post (2.1.1)
+    nokogiri (1.11.1)
+      mini_portile2 (~> 2.5.0)
+      racc (~> 1.4)
     nokogiri (1.11.1-x86_64-darwin)
       racc (~> 1.4)
     optout (0.0.2)
@@ -291,7 +297,7 @@ GEM
       unf_ext (>= 0.0.7.7)
     relaton-w3c (1.7.0)
       relaton-bib (>= 1.7.0)
-    rexml (3.2.4)
+    rexml (3.2.5)
     rice (2.2.0)
     roman-numerals (0.3.0)
     ruby-graphviz (1.2.5)