diff --git a/derp/derp.go b/derp/derp.go
index f3f73c455..b5fadede1 100644
--- a/derp/derp.go
+++ b/derp/derp.go
@@ -44,10 +44,6 @@ const (
 //   * version 2: received packets have src addrs in frameRecvPacket at beginning
 const protocolVersion = 2
 
-const (
-	protocolSrcAddrs = 2 // protocol version at which client expects src addresses
-)
-
 // frameType is the one byte frame type at the beginning of the frame
 // header.  The second field is a big-endian uint32 describing the
 // length of the remaining frame (not including the initial 5 bytes).
diff --git a/derp/derp_server.go b/derp/derp_server.go
index 2658f01c3..fbc9fa8df 100644
--- a/derp/derp_server.go
+++ b/derp/derp_server.go
@@ -614,10 +614,8 @@ func (c *sclient) handleFrameSendPacket(ft frameType, fl uint32) error {
 	}
 
 	p := pkt{
-		bs: contents,
-	}
-	if dst.info.Version >= protocolSrcAddrs {
-		p.src = c.key
+		bs:  contents,
+		src: c.key,
 	}
 	return c.sendPkt(dst, p)
 }