Camfrog has announced the discontinuation of Camfrog 3.X in order for bandwidth and resources to be streamlined. Since the release of Camfrog 5.x users viewing camfrog 3.X and viewing Camfrog 5.X users had the effect of doubling the bandwidth being used and cpu load of the 5.X users as the 5.X has to send out a 5.X stream as well as a 3.X stream.
This effect has also placed increased bandwidth load on the servers and by upgrading to the 5.X client there will be an all round improvement for users and servers alike.
For this reason all 3.X users must upgrade to 5.X and Camfrog 3.X users will find themselves blocked when trying to log on to the server.
The Camfrog blog has also advised in coming weeks support for Camfrog 4.X will end and it will also be blocked.
Read more here Camfrog 3.x No Longer Supported
You can upgrade to Camfrog 5.1 here Download Camfrog 5.1