We are currently running Sage 100 v. 2013 perpetual license.  We renewed our contract and changed to 100c as we eventually want to upgrade to premium.  We also want to upgrade to 2018, but we have a lot of customization, so we want to don't want to make the changes all at once.  I was told we could change to 100c, then upgrade to 2018 at a later date.  But now we are being told 100c is only on versions 2016 and later.  I have been told the only difference with 100c is the UI and the credit card processing connection, but I am not confident that is a "simple" change that won't cause any issues when we go live.  My question is, is it not possible to change to 100c only, without any other changes, then upgrade to 2018 later?