Level 2 Contributor

Exchange 2013 CU Updates

Exchange 2013 CU Updates
Dear Support,

We have exchange 2013 Cu8 currently running.

we have 3 mailbox server and 3 cas servers with same CU8. Now we are planing to upgrade the CU.

question 1= i can directly upgrade exchange 2013 CU from 8 to 2013 CU21 (15.00.1395.004) right? please correct me.

Question 2= i can update first Cas servers and then Mailbox servers respectively right?

Question 3= please share the best practice steps to how i can upgrade CU is there any imapct will be?

Thanks a lot.
Level 1 Contributor


Yes you can do it.


Update Mailbox 1st and then go to CAS server

Q3: CU21


Prereq .net 4.7.1

1. Take backup of your AD (system State) & Exchange DBs

2. Upgrade your schema 1st and allow for replication to your other DC

3.  Now upgrade your passive mailbox server.

4. Now move active DB's to passive server & upgrade the last remaining server

5. Now go to CAS servers.


Microsoft Recommended N-1 (Which is CU20)

Check for more info:


Level 2 Contributor

Dear Support,

i really appreciate your prompt support, i have some doubts please clear it.

Que1= you have mentioned "Microsoft Recommended N-1 (Which is CU20)" means need to update CU 20 will be better instead of CU 21?


Que2= Also in CU 20 i saw mentioned  TLS Exchange Server Support for TLS 1.2, if i update CU 20 or later then becouse of TLS 1.2 is there any impact will be on my exchange?? 


Que 3= Is there really need  VC++ 2013 runtime to install?


Thanks a lot