We have released a page where we post all new GNU Radio 3.8 series, compiled for Windows. There has been many modifications between 3.7 and 3.8 branches, in particular to those related with GUI aspects.
Compiling from scratch GNU Radio 3.8 is not an easy task. But distributing it does! All distributions you can download from this page are clean distributions. All are downloaded from their github repository, with no additional modifications or 3rd-party modules/addons.
Hope you enjoy!