Need an iRule to skip Kerberos Authentication for MAC

Uncertain if this helps any? Yet have had to work through a number of on-premise hosted Sharepoint issues last few years for MACs specifically. The following has worked 'mostly' to re-negotiate NTLM. Believe it's still compatible with Office 2016 client apps. Though M$oft change things around...often. E.g.:

when HTTP_REQUEST {
set useragent [string tolower [HTTP::header value "User-Agent"]]
if { ([string length $useragent] < 50) || (($useragent contains "mac") && !($useragent contains "mozilla")) || (($useragent contains "macintosh") && ($useragent contains "microsoft")) }{ 
      if {($sid == "") || ($useragent contains "macintosh")}{
         switch -glob $useragent {              
            "microsoft office" -
            "*microsoft document connection*" -
            "*microsoft office word*" -
            "*microsoft office excel*" -
            "*microsoft office powerpoint*" -
            "microsoft office existence discovery" -
            "microsoft office protocol discovery" -
            "*webdavfs*" -
            "*word*" -
            "*excel*" -
            "*powerpoint*" -
            "*onenote*" -
            "*webdavlib*" {             
               ACCESS::disable
               if { ([HTTP::method] == "OPTIONS") && ([HTTP::header value 
                                Authorization] == "Bearer") }{
                  set mac_auth 1
               } 
            }
         }   
      }
   }
when HTTP_RESPONSE {
   if { ($mac_auth != "") }{
      HTTP::respond 401 WWW-Authenticate "NTLM"
      set mac_auth ""
   }
}