diff --git a/scripts/alphanet_version b/scripts/alphanet_version
index 66e7e307b..2c65daa94 100644
--- a/scripts/alphanet_version
+++ b/scripts/alphanet_version
@@ -1 +1 @@
-2017-08-17
+2017-09-21
diff --git a/scripts/gen_genesis.ml b/scripts/gen_genesis.ml
new file mode 100644
index 000000000..e366d8f0a
--- /dev/null
+++ b/scripts/gen_genesis.ml
@@ -0,0 +1,8 @@
+
+let prefix = "BLockGenesisGenesisGenesisGenesisGenesis"
+let suffix = "BBBBB"
+let p = Base58.raw_decode (prefix ^ suffix ^ "crcCRC")
+let p = String.sub p 0 (String.length p - 4)
+let p = Base58.safe_encode p
+let () = print_endline p
+
diff --git a/src/node/main/node_run_command.ml b/src/node/main/node_run_command.ml
index 4600c1678..f1a387955 100644
--- a/src/node/main/node_run_command.ml
+++ b/src/node/main/node_run_command.ml
@@ -11,10 +11,10 @@ open Logging.Node.Main
 
 let genesis : State.Net.genesis = {
   time =
-    Time.of_notation_exn "2016-11-01T00:00:00Z" ;
+    Time.of_notation_exn "2017-09-21T00:00:00Z" ;
   block =
     Block_hash.of_b58check_exn
-      "BLockGenesisGenesisGenesisGenesisGenesisGeneskvg68z" ;
+      "BLockGenesisGenesisGenesisGenesisGenesisBBBBBbwcZMg" ;
   protocol =
     Protocol_hash.of_b58check_exn
       "ProtoGenesisGenesisGenesisGenesisGenesisGenesk612im" ;
diff --git a/src/node/shell/distributed_db_message.ml b/src/node/shell/distributed_db_message.ml
index 91ec4e034..5b148b59d 100644
--- a/src/node/shell/distributed_db_message.ml
+++ b/src/node/shell/distributed_db_message.ml
@@ -174,7 +174,7 @@ let versions =
   let open P2p.Version in
   [ { name = "TEZOS" ;
       major = 0 ;
-      minor = 21 ;
+      minor = 23 ;
     }
   ]
 
diff --git a/src/utils/hash.ml b/src/utils/hash.ml
index 3c88e93cb..583d4881c 100644
--- a/src/utils/hash.ml
+++ b/src/utils/hash.ml
@@ -543,11 +543,13 @@ module Net_id = struct
 
   let size = 4
 
-  let of_block_hash bh =
+  let extract bh =
     MBytes.substring (Block_hash.to_bytes bh) 0 4
 
-  let hash_bytes l = of_block_hash (Block_hash.hash_bytes l)
-  let hash_string l = of_block_hash (Block_hash.hash_string l)
+  let hash_bytes l = extract (Block_hash.hash_bytes l)
+  let hash_string l = extract (Block_hash.hash_string l)
+
+  let of_block_hash bh = hash_bytes [Block_hash.to_bytes bh]
 
   type Base58.data += Hash of t