Hi,
The bridge authority Serge has upgraded to tor-0.4.8.12 and it's now rejecting bridges running tor-0.4.7.x (end-of-life).
Please upgrade your bridge to tor 0.4.8.x to return to the network.
Bridges affected: https://metrics.torproject.org/rs.html#search/type:bridge%20version:0.4.7%20
Gus
tor-relays@lists.torproject.org