Exchange ActiveSync during co-exsistance

Hello Everyone,

We currently have Exchange 2007 in place and are going to install Exchange 2013 using IIS ARR as reverse proxy and load balancing. One concern we have is how the co-existence will effect ActiveSync users. Once we change our NAT entry for Autodiscover to point to Exchange 2013 sever and change our DNS entries how will ActiveSync users mobile devices accept the change? Will they re-poll Autodiscover and get the new configuration or will they need to remove the account and re-add it?

Thanks for any information you can provide,

Ian...