eDir to AD

Currently Build 222 but we will update this to 280 soon.
Back end is 18.0.1 129782

We want to move to AD from eDir.
When re remove the group (326 users) on the eDir side and re-add to a AD group, will the phones have to be touched?
I realize even if it should, some of them will probably break.
Often the users who deem email to be super important on their phones.