Those configuring IM integration for OWA and Lync or Skype for Business know the drill of editing the web.config files on your Exchange servers and configuring the certificate thumbprint and Lync/SfB pool? That especially became a nuisance as after each Cumulative Update those settings needed to be reconfigured, for which I wrote a Configure-IMIntegration script.

The Exchange team has obviously listened to feedback from customers and made this setting persistent in Exchange 2016. No longer is it required to dive in those web.config files after installing each CU. Instead, you now configure these settings using the Set-Override cmdlet, which will store the setting in Active Directory.

For example:

New-SettingOverride -Name '<Description>' -Server <Server/Wildcard> -Component OwaServer -Section IMSettings -Parameters @("IMServerName=<Server/Pool FQDN>","IMCertificateThumbprint=<Certificate Thumbprint>") -Reason "<Reason>" -MinVersion "<Minimum Version To Apply To>" -MaxVersion "Maximum Version to Apply To"
Get-ExchangeDiagnosticInfo -Process Microsoft.Exchange.Directory.TopologyService -Component VariantConfiguration -Argument Refresh

For example, to configure the override for all servers with a name starting with EX16, configuring lync.contoso.com as pool FQDN and a specific thumbprint, only for Exchange builds starting at 15.1.225.42 (Exchange 2016 RTM), you could use:

New-SettingOverride -Name 'IM Integration' -Server EX16* -Component OwaServer -Section IMSettings -Parameters @("IMServerName=lync.contoso.com","IMCertificateThumbprint=12345678123412341234567812345678123126789") -Reason "Configure IM" -MinVersion "15.01.0225.42"
Get-ExchangeDiagnosticInfo -Process Microsoft.Exchange.Directory.TopologyService -Component VariantConfiguration -Argument Refresh

Finally, restart the OWA App pool to have OWA reread the new settings:

Restart-WebAppPool MSExchangeOWAApppool