diff --git a/app/controllers/dmsf_state_controller.rb b/app/controllers/dmsf_state_controller.rb
index e3551e56..4f2efecd 100644
--- a/app/controllers/dmsf_state_controller.rb
+++ b/app/controllers/dmsf_state_controller.rb
@@ -49,7 +49,7 @@ class DmsfStateController < ApplicationController
   private
   
   def format_valid?(format)
-    format.blank? || ((format =~ /%(t|d|v|i|r)/) && format.length < 256)
+    format.blank? || ((/%(t|d|v|i|r)/.match?(format)) && format.length < 256)
   end
 
 end
\ No newline at end of file
diff --git a/app/helpers/dmsf_helper.rb b/app/helpers/dmsf_helper.rb
index 0f7ec4e3..a3af0d0c 100644
--- a/app/helpers/dmsf_helper.rb
+++ b/app/helpers/dmsf_helper.rb
@@ -48,11 +48,13 @@ module DmsfHelper
     # get only the filename, not the whole path
     just_filename = File.basename(filename.gsub('\\\\', '/'))
     # replace all non alphanumeric, hyphens or periods with underscore
-    just_filename = just_filename.gsub(/[^\w\.\-]/,'_')
-    unless just_filename =~ %r{^[a-zA-Z0-9_\.\-]*$}
+    just_filename.gsub!(/[^\w\.\-]/, '_')
+    unless %r{^[a-zA-Z0-9_\.\-]*$}.match?(just_filename)
       # keep the extension if any
-      extension = $1 if just_filename =~ %r{(\.[a-zA-Z0-9]+)$}
-      just_filename = Digest::SHA256.hexdigest(just_filename)  << extension
+      if just_filename =~ %r{(\.[a-zA-Z0-9]+)$}
+        extension = $1
+        just_filename = Digest::SHA256.hexdigest(just_filename) << extension
+      end
     end
     just_filename
   end
diff --git a/app/validators/dmsf_file_name_validator.rb b/app/validators/dmsf_file_name_validator.rb
index 5996dbc7..7e9b0411 100644
--- a/app/validators/dmsf_file_name_validator.rb
+++ b/app/validators/dmsf_file_name_validator.rb
@@ -22,7 +22,7 @@
 class DmsfFileNameValidator  < ActiveModel::EachValidator
 
   def validate_each(record, attribute, value)
-    unless value =~ /\A[^#{DmsfFolder::INVALID_CHARACTERS}]*\z/
+    unless /\A[^#{DmsfFolder::INVALID_CHARACTERS}]*\z/.match?(value)
       record.errors.add attribute, :error_contains_invalid_character
     end
   end