Hi Reza!

Take a look at our knowledge base article Migrate SmarterMail to a Different Server for instructions on moving to the new server. Once you've migrated everything over and ensure mail is working you can upgrade your installation. You'll find instructions to upgrade your installation in our online help here: Installation and Upgrade. Once on that page, click on the Upgrade Process option in the "Jump To" menu at the top of the page, that will take you directly to the instructions you need.