Changing client auth type in exchange 2010

Hi chaps,

We have an exchange 2010 server and it's outlook-anywhere has been set up to use basic authentication. The Outlook clients are autoconfigured to use Outlook Anywhere using Basic authentication. In Exchange 2007 you could specify both basic and NTLM, however in 2010 you seem to only be able to specify NTLM *or* basic.

This is the output of get-outlookanywhere (chopped off on the right hand side in case you are wondering);

RunspaceId                 : 32eb15b8-c829-48fe-af20-b68c2faa8d42
ServerName                 : myserver
SSLOffloading              : False
ExternalHostname           : myserver.mydomain.com
ClientAuthenticationMethod : Basic
IISAuthenticationMethods   : {Basic}
MetabasePath               : IIS://myserver.mydomain.local/W3SVC/1/ROOT/Rpc
Path                       : C:\Windows\System32\RpcProxy
Server                     : myserver
AdminDisplayName           :
ExchangeVersion            : 0.10 (14.0.100.0)
Name                       : Rpc (Default Web Site)
DistinguishedName          : CN=Rpc (Default Web Site),CN=HTTP,CN=Protoc
                             ative Group (FYDIBOHF23SPDLT),CN=Administra
                             Exchange,CN=Services,CN=Configuration,DC=ki
Identity                   : myserver\Rpc (Default Web Site)
Guid                       : 6d65db02-bf7f-44d5-aba9-16b39d9f898d
ObjectCategory             : mydomain.local/Configuration/Schema/ms-Exch-Rp
ObjectClass                : {top, msExchVirtualDirectory, msExchRpcHttp
WhenChanged                : 11/02/2010 13:05:31
WhenCreated                : 08/02/2010 21:58:09
WhenChangedUTC             : 11/02/2010 13:05:31
WhenCreatedUTC             : 08/02/2010 21:58:09
OrganizationId             :
OriginatingServer          : my-old-server.mydomain.local
IsValid                    : True

If we change this to NTLM will it effect any of the mobile phones we have out there ? (mainly iPhones) and will Outlook auto-detect the change or will we need to update each one manually to use NTLM rather than basic (theres about 100 or so).

Olly