Index: app/models/mail_handler.rb
===================================================================
--- app/models/mail_handler.rb	(revision 17991)
+++ app/models/mail_handler.rb	(working copy)
@@ -43,10 +43,8 @@
     options[:no_notification] = (options[:no_notification].to_s == '1')
     options[:no_permission_check] = (options[:no_permission_check].to_s == '1')
 
-    raw_mail.force_encoding('ASCII-8BIT')
-
     ActiveSupport::Notifications.instrument("receive.action_mailer") do |payload|
-      mail = Mail.new(raw_mail)
+      mail = Mail.new(raw_mail.b)
       set_payload_for_mail(payload, mail)
       new.receive(mail, options)
     end
Index: lib/redmine/codeset_util.rb
===================================================================
--- lib/redmine/codeset_util.rb	(revision 17991)
+++ lib/redmine/codeset_util.rb	(working copy)
@@ -16,8 +16,7 @@
 
     def self.to_utf8(str, encoding)
       return if str.nil?
-      str = str.dup
-      str.force_encoding("ASCII-8BIT")
+      str = str.b
       if str.empty?
         str.force_encoding("UTF-8")
         return str
@@ -41,8 +40,7 @@
 
     def self.to_utf8_by_setting_internal(str)
       return if str.nil?
-      str = str.dup
-      str.force_encoding('ASCII-8BIT')
+      str = str.b
       return str if str.empty?
       return str if /\A[\r\n\t\x20-\x7e]*\Z/n.match(str) # for us-ascii
       str.force_encoding('UTF-8')
Index: lib/redmine/export/pdf.rb
===================================================================
--- lib/redmine/export/pdf.rb	(revision 17991)
+++ lib/redmine/export/pdf.rb	(working copy)
@@ -134,9 +134,7 @@
       class RDMPdfEncoding
         def self.rdm_from_utf8(txt, encoding)
           txt ||= ''
-          txt = Redmine::CodesetUtil.from_utf8(txt, encoding)
-          txt.force_encoding('ASCII-8BIT')
-          txt
+          Redmine::CodesetUtil.from_utf8(txt, encoding).b
         end
 
         def self.attach(attachments, filename, encoding)
Index: lib/redmine/scm/adapters/bazaar_adapter.rb
===================================================================
--- lib/redmine/scm/adapters/bazaar_adapter.rb	(revision 17991)
+++ lib/redmine/scm/adapters/bazaar_adapter.rb	(working copy)
@@ -45,7 +45,7 @@
           end
 
           def scm_command_version
-            scm_version = scm_version_from_command_line.dup.force_encoding('ASCII-8BIT')
+            scm_version = scm_version_from_command_line.b
             if m = scm_version.match(%r{\A(.*?)((\d+\.)+\d+)})
               m[2].scan(%r{\d+}).collect(&:to_i)
             end
@@ -98,8 +98,7 @@
           scm_cmd(*cmd_args) do |io|
             prefix_utf8 = "#{url}/#{path}".tr('\\', '/')
             logger.debug "PREFIX: #{prefix_utf8}"
-            prefix = scm_iconv(@path_encoding, 'UTF-8', prefix_utf8)
-            prefix.force_encoding('ASCII-8BIT')
+            prefix = scm_iconv(@path_encoding, 'UTF-8', prefix_utf8).b
             re = %r{^V\s+(#{Regexp.escape(prefix)})?(\/?)([^\/]+)(\/?)\s+(\S+)\r?$}
             io.each_line do |line|
               next unless line =~ re
Index: lib/redmine/scm/adapters/cvs_adapter.rb
===================================================================
--- lib/redmine/scm/adapters/cvs_adapter.rb	(revision 17991)
+++ lib/redmine/scm/adapters/cvs_adapter.rb	(working copy)
@@ -45,7 +45,7 @@
           end
 
           def scm_command_version
-            scm_version = scm_version_from_command_line.dup.force_encoding('ASCII-8BIT')
+            scm_version = scm_version_from_command_line.b
             if m = scm_version.match(%r{\A(.*?)((\d+\.)+\d+)}m)
               m[2].scan(%r{\d+}).collect(&:to_i)
             end
@@ -93,7 +93,7 @@
         def entries(path=nil, identifier=nil, options={})
           logger.debug "<cvs> entries '#{path}' with identifier '#{identifier}'"
           path_locale = scm_iconv(@path_encoding, 'UTF-8', path)
-          path_locale = path_locale.dup.force_encoding("ASCII-8BIT")
+          path_locale = path_locale.b
           entries = Entries.new
           cmd_args = %w|-q rls -e|
           cmd_args << "-D" << time_to_cvstime_rlog(identifier) if identifier
Index: lib/redmine/scm/adapters/git_adapter.rb
===================================================================
--- lib/redmine/scm/adapters/git_adapter.rb	(revision 17991)
+++ lib/redmine/scm/adapters/git_adapter.rb	(working copy)
@@ -49,7 +49,7 @@
           end
 
           def scm_command_version
-            scm_version = scm_version_from_command_line.dup.force_encoding('ASCII-8BIT')
+            scm_version = scm_version_from_command_line.b
             if m = scm_version.match(%r{\A(.*?)((\d+\.)+\d+)})
               m[2].scan(%r{\d+}).collect(&:to_i)
             end
Index: lib/redmine/scm/adapters/mercurial_adapter.rb
===================================================================
--- lib/redmine/scm/adapters/mercurial_adapter.rb	(revision 17991)
+++ lib/redmine/scm/adapters/mercurial_adapter.rb	(working copy)
@@ -58,7 +58,7 @@
             # The hg version is expressed either as a
             # release number (eg 0.9.5 or 1.0) or as a revision
             # id composed of 12 hexa characters.
-            theversion = hgversion_from_command_line.dup.force_encoding('ASCII-8BIT')
+            theversion = hgversion_from_command_line.b
             if m = theversion.match(%r{\A(.*?)((\d+\.)+\d+)})
               m[2].scan(%r{\d+}).collect(&:to_i)
             end
@@ -270,8 +270,7 @@
           blame = Annotate.new
           hg 'rhannotate', '-ncu', "-r#{CGI.escape(hgrev(identifier))}", '--', hgtarget(p) do |io|
             io.each_line do |line|
-              line.force_encoding('ASCII-8BIT')
-              next unless line =~ %r{^([^:]+)\s(\d+)\s([0-9a-f]+):\s(.*)$}
+              next unless line.b =~ %r{^([^:]+)\s(\d+)\s([0-9a-f]+):\s(.*)$}
               r = Revision.new(:author => $1.strip, :revision => $2, :scmid => $3,
                                :identifier => $3)
               blame.add_line($4.rstrip, r)
Index: lib/redmine/scm/adapters/subversion_adapter.rb
===================================================================
--- lib/redmine/scm/adapters/subversion_adapter.rb	(revision 17991)
+++ lib/redmine/scm/adapters/subversion_adapter.rb	(working copy)
@@ -48,7 +48,7 @@
           end
 
           def svn_binary_version
-            scm_version = scm_version_from_command_line.dup.force_encoding('ASCII-8BIT')
+            scm_version = scm_version_from_command_line.b
             if m = scm_version.match(%r{\A(.*?)((\d+\.)+\d+)})
               m[2].scan(%r{\d+}).collect(&:to_i)
             end