This change takes effect today (Aug 18, 2014).
As a result of this change, you may see content that is already in the archive reappear on the updates page. It is safe to re-add these to the archive. The only change this would cause is for the archival date of the content to be updated. The existing content will simply be overwritten by new one.
Those who have already built their receivers need not take any action. Librarian can already work with unsigned files.
Until today, Outernet has used gpg-signed files for broadcast. However, we have discovered that client-side decryption of large numbers of such files is inefficient and prone to race conditions, and we are switching to unsigned .zip files until we figure out whether we need this type of security measure and find a more efficient way to do it if we do (one option is to ship signatures separately, but then we can’t really guarantee that signatures will be delivered along with content).
The signed files have been removed from broadcast and unsigned files are being uploaded, so you may experience a brief interruption in broadcast.
Also, future versions of Librarian will be stripped of code related to decrypting and verifying signed files, so it may actually run a little bit faster, and, more importantly, won’t have any dependency on GnuPG.