Peer Caching - Client Updates Low Speed Sites
Peer Caching, similar to Microsoft Bit caching
The Background Intelligent Transfer Service (BITS) helps you transfer large amounts of data without degrading network performance. It does this by transferring data in small chunks, utilizing unused bandwidth as it becomes available, and reassembling the data at the destination
Would be ideal for small remote sites with low bandwidth speeds and no remote server to install the update cache sophos client.