To get the latest version of Exchange 2013, download and install Microsoft Exchange Server 2013 Cumulative Update 23. Because each CU is a full installation of Exchange and includes updates and changes from all previous CUs, you don't need to install any previous CUs or service packs first.
And the links peovided above should be helpful to you. Below is an article which include step-by-step guide to upgrade your Exchange server to the latest CU for your reference:
Exchange 2013 Cumulative Update installation tips and best practices
Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.
After you upgrade your server to CU23, install the Security Update For Exchange Server 2013 CU23 (KB5000871)
1.Disable the anti-virus software.
2.Open an elevated Command Prompt window (not PowerShell) as an administrator, like this:
- Select Start and then enter cmd .
- Right-click Command Prompt in the results and select Run as administrator .
- If the User Account Control dialog box appears, select Yes and then Next .
3.At the command prompt, enter the full path to the folder that contains the 'MSP file', then press 'Enter'.
Note: Do not double-click the 'MSP file' to run it.
4.When the installation is complete, re-enable the antivirus software and restart your computer. (The installation program may prompt you to restart.)
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