-Note that if at all possible, start the configuration process from scratch.
-It is less prone to missing configuration options than copying your old
-configuration. The ideal solution would be to copy your users' preference
-files, and then run conf.pl to re-configure SquirrelMail (without using the
-old config file). If you do copy the config.php file, you will want to run
-conf.pl and check for new options.
+C. Copy plugins
+
+Like SquirrelMail, plugins are frequently updated for improvements, as well
+as to make them compatible with new SquirrelMail releases. It is suggested
+that you download new versions of your plugins at the same time you download
+your SquirrelMail install, and that you install your plugins fresh (it's
+easy, don't panic!).
+
+You should not try replacing plugins that are already included in SquirrelMail
+package. Download latest versions of plugins that are not included in new
+SquirrelMail package or copy them from older SquirrelMail install.
+
+D. Copy themes
+
+If you've created or modified themes, you should copy just those to the new
+SquirrelMail themes directory. To just copy them all over to the new
+SquirrelMail installation, you can run one command.
+
+ $ cp -ui squirrelmail-1.2.6.bak/themes/* squirrelmail-1.4.0/themes/
+
+When -u flag is used, command copies only missing and newer files.
+When -i flag is used, command asks for confirmation before replacing
+existing files.