I hope someone here may be able to answer this. I am using a MacBook (2016) and an iMac (2015). Of course the MacBook has a solid state drive, and would be converted to APFS on upgrading to High Sierra. That machine hasn't been upgraded yet. The iMac has a fusion drive, and remains HFS+ following the upgrade to High Sierra. No problems with that upgrade, BTW. I use iCloud to sync files between the two machines. So... What issues will I likely encounter given the laptop will be APFS, and the iMac remains HFS+? Thx.