Julia nightly 1.7 vs 1.6

I tried building Julia 1.6 the other day on Windows but failed(only the 32bit version was successful), so I decided to give up and try the nightly build, which, surprisingly, is the 1.7 DEV version. Does the 1.7 contain all the features of 1.6 + more (with the obvious risks of some packages not working of course)?

1.6 has just been branched off the master branch, and at that point the master turned to 1.7. At the point of branching, 1.6 and 1.7 were essentially the same, now they start diverging with every new nightly build that includes whatever PRs are merged onto master.