Let’s assume that we have

ex01.itforce.local and ex02.itforce.local Exchange 2016 servers in DAG cluster. We need to install new CU on this cluster without downtime. (assumed that all CAS, smtp protocols are properly loadbalanced). So we need:

1. at first disable all workloads/switch to maintenance mode on the node ex01,
2. install CU on ex01,
3. reboot ex01
4. exit from maintenance mode on ex01
5. enter into maintenance mode on ex02
6. install CU on ex02,
7. reboot ex02
8. exit from maintenance mode on ex02
9. equally spread workload on both nodes again

#goto ex01
#run in elevated mode powershell for exchange

#prepare smtp transport:
Set-ServerComponentState ex01 

Only for last day:

$logentries = Search-AdminAuditLog -StartDate (Get-Date).AddDays(-1)

$logentries | Select RunDate,Caller,CmdletName,@{Name=’CmdletParameters’;Expression={[string]::join(“;”, ($_.CmdletParameters))}},ObjectModified, OriginatingServer | sort rundate | export-csv -NoTypeInformation -path c:\temp\adminauditlog.csv

#Unhide in bulk, if you have ready csv with Primary smtp email addresses:

$users = import-csv C:\temp\hidden.csv
Foreach($_ in $users) {Set-mailbox -identity $_.PrimarySmtpAddress -HiddenFromAddressListsEnabled $false}

# find all hidden mailboxes for whole AD  and show AD user’s Enabled/Disabled status, plus with location (in what OU)

get-mailbox -resultsize unlimited | where {($_.IsMailboxEnabled -eq "True") -and ($_.HiddenFromAddressListsEnabled -eq "True" )} | select-object name, samaccountname, @{N="ADAccount-Is-Enabled"; E={(get-aduser -Identity $_.samaccountname).enabled}}, PrimarySmtpAddress, IsMailboxEnabled , HiddenFromAddressListsEnabled, OrganizationalUnit| export-csv -path c:\temp\hidden.csv -NoTypeInformation