Apple has somewhat relented to criticism about removing Apps and Ringtones syncing in iTunes 12.7 and has made iTunes 12.6.3 available with these abilities. iTunes 12.6.3 will install over iTunes 12.7, unlike the non-trivial process previously required to downgrade back to 12.6.2.
I suppose that for people who felt ambushed by installing iTunes 12.7 and weren’t able to get their Apps and Ringtones in order, this will enable some extra time to do so. But I wouldn’t want to stick around on this version. Apple has warned that 12.6.3 won’t provide notifications for future updates and it presumably does not have 12.7’s new features and fixes. So once you’ve made any adjustments (say, getting your Fabulous Ringtones Collection uploaded in toto to your devices, extricated older iOS apps and so on) you may want to upgrade back to 12.7.