By default blockerDNS signs the Apple configuration profiles you download. This means that you (or your iPhone) can verify that the profile really is from blockerDNS and not a third-party that could potentially point you to sketchy DNS servers.
Unsigned profiles aren't automatically bad though. They can actually be useful because you can edit them yourself to further customize your settings. If you take a look at a configuration profile you'll see that it's nothing more than a text file with your blockerDNS username and some server info.
Note: If you edit a signed profile it'll break the signing verification, since it would no longer be the original file we signed and you downloaded.
You can download both signed and unsigned profiles below
Signed profiles will be clearly marked
Unsigned profiles will also be clearly marked