Enable UTF8=ACCEPT if the server supports ENABLE (and UTF=ACCEPT).

lib/mail/network/retriever_methods/imap.rb

@@ -179,6 +179,8 @@ def start(config=Mail::Configuration.instance, &block)
           imap.authenticate(settings[:authentication], settings[:user_name], settings[:password])
         end
 
+        imap.enable :utf8 if imap.capable?("ENABLE")
+
         yield imap
       ensure
         if defined?(imap) && imap && !imap.disconnected?

spec/mail/network/retriever_methods/imap_spec.rb

@@ -318,5 +318,18 @@
     end
   end
 
+
+  describe "UTF8=ACCEPT support" do
+    before(:each) do
+      @imap = MockIMAP.new
+      allow(MockIMAP).to receive(:new).and_return(@imap)
+      allow(@imap).to receive(:capable?).with("ENABLE").and_return(true)
+    end
+    it "should enable UTF8=ACCEPT" do
+      expect(@imap).to receive(:enable).with(:utf8)
+      messages = Mail.find
+    end
+  end
+
 end
 

spec/spec_helper.rb

@@ -319,6 +319,10 @@ def expunge
     @@marked_for_deletion = []
   end
 
+  def capable?(name)
+    false
+  end
+
   def self.mailbox; @@mailbox end    # test only
   def self.readonly?; @@readonly end # test only