updating exchange server 2013

I have just inherited an Exchange server 2013 installation that hasn't been patched for sometime it is sitting at CU13 I want to bring it up to the latest, CU21 how do I go about it
Barry FieldsIT managerAsked:
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Jose Gabriel Ortega CastroEE Solution Guide/Topic Advisor and CEO Faru Bonon ITCommented:
Basically, that's a new install of Exchange just do a backup, warn your users and proceed.

Here's the detailed about the CU21 what it needs

https://support.microsoft.com/en-us/help/4099855/cumulative-update-21-for-exchange-server-2013
Danilo AndradeIT Systems AnalystCommented:
It is a fairly simple process. You can follow this article if you are looking for some sort of step-by-step guide:
https://www.oxfordsbsguy.com/2015/12/20/exchange-2013-cumulative-update-installation-tips-best-practices/

I personally like to do it all from the GUI by running the executable, but you can do it all from CMD. Just make sure you have a good backup of the server, and after the upgrade is done make sure to test connectivity (autodiscover) and check if your valid SSL certificate is still applied.
Hani M .S. Al-habshiContributor as IT ExpertCommented:
1-Download new CU
2-install new CU.exe
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Barry FieldsIT managerAuthor Commented:
I do not have to do CU's incrementally, just jump to CU21?
Danilo AndradeIT Systems AnalystCommented:
Just go directly to CU21. No need to do any in between.

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Barry FieldsIT managerAuthor Commented:
Thank you
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