diff --git a/mercurial/help/internals/wireprotocol.txt b/mercurial/help/internals/wireprotocol.txt
--- a/mercurial/help/internals/wireprotocol.txt
+++ b/mercurial/help/internals/wireprotocol.txt
@@ -1670,6 +1670,16 @@
 TODO require node type be specified, as N bytes of binary node value
 could be ambiguous once SHA-1 is replaced.
 
+branchmap
+---------
+
+Obtain heads in named branches.
+
+Receives no arguments.
+
+The response is a map with bytestring keys defining the branch name.
+Values are arrays of bytestring defining raw changeset nodes.
+
 heads
 -----
 
diff --git a/mercurial/wireproto.py b/mercurial/wireproto.py
--- a/mercurial/wireproto.py
+++ b/mercurial/wireproto.py
@@ -828,7 +828,8 @@
 
     return wireprototypes.bytesresponse(''.join(r))
 
-@wireprotocommand('branchmap', permission='pull')
+@wireprotocommand('branchmap', permission='pull',
+                  transportpolicy=POLICY_V1_ONLY)
 def branchmap(repo, proto):
     branchmap = repo.branchmap()
     heads = []
@@ -1210,6 +1211,14 @@
 
 # Wire protocol version 2 commands only past this point.
 
+@wireprotocommand('branchmap', permission='pull',
+                  transportpolicy=POLICY_V2_ONLY)
+def branchmapv2(repo, proto):
+    branchmap = {encoding.fromlocal(k): v
+                 for k, v in repo.branchmap().iteritems()}
+
+    return wireprototypes.cborresponse(branchmap)
+
 @wireprotocommand('heads', args='publiconly', permission='pull',
                   transportpolicy=POLICY_V2_ONLY)
 def headsv2(repo, proto, publiconly=False):
diff --git a/tests/test-wireproto-command-branchmap.t b/tests/test-wireproto-command-branchmap.t
new file mode 100644
--- /dev/null
+++ b/tests/test-wireproto-command-branchmap.t
@@ -0,0 +1,72 @@
+  $ . $TESTDIR/wireprotohelpers.sh
+
+  $ hg init server
+  $ enablehttpv2 server
+  $ cd server
+  $ hg debugdrawdag << EOF
+  > C D
+  > |/
+  > B
+  > |
+  > A
+  > EOF
+
+  $ hg up B
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg branch branch1
+  marked working directory as branch branch1
+  (branches are permanent and global, did you want a bookmark?)
+  $ echo b1 > foo
+  $ hg -q commit -A -m 'branch 1'
+  $ hg up B
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ hg branch branch2
+  marked working directory as branch branch2
+  $ echo b2 > foo
+  $ hg -q commit -A -m 'branch 2'
+
+  $ hg log -T '{rev}:{node} {branch} {desc}\n'
+  5:224161c7589aa48fa83a48feff5e95b56ae327fc branch2 branch 2
+  4:b5faacdfd2633768cb3152336cc0953381266688 branch1 branch 1
+  3:be0ef73c17ade3fc89dc41701eb9fc3a91b58282 default D
+  2:26805aba1e600a82e93661149f2313866a221a7b default C
+  1:112478962961147124edd43549aedd1a335e44bf default B
+  0:426bada5c67598ca65036d57d9e4b64b0c1ce7a0 default A
+
+  $ hg serve -p $HGPORT -d --pid-file hg.pid -E error.log
+  $ cat hg.pid > $DAEMON_PIDS
+
+No arguments returns something reasonable
+
+  $ sendhttpv2peer << EOF
+  > command branchmap
+  > EOF
+  creating http peer for wire protocol version 2
+  sending branchmap command
+  s>     POST /api/exp-http-v2-0001/ro/branchmap HTTP/1.1\r\n
+  s>     Accept-Encoding: identity\r\n
+  s>     accept: application/mercurial-exp-framing-0003\r\n
+  s>     content-type: application/mercurial-exp-framing-0003\r\n
+  s>     content-length: 24\r\n
+  s>     host: $LOCALIP:$HGPORT\r\n (glob)
+  s>     user-agent: Mercurial debugwireproto\r\n
+  s>     \r\n
+  s>     \x10\x00\x00\x01\x00\x01\x01\x11\xa1DnameIbranchmap
+  s> makefile('rb', None)
+  s>     HTTP/1.1 200 OK\r\n
+  s>     Server: testing stub value\r\n
+  s>     Date: $HTTP_DATE$\r\n
+  s>     Content-Type: application/mercurial-exp-framing-0003\r\n
+  s>     Transfer-Encoding: chunked\r\n
+  s>     \r\n
+  s>     78\r\n
+  s>     p\x00\x00\x01\x00\x02\x01F
+  s>     \xa3Gbranch1\x81T\xb5\xfa\xac\xdf\xd2c7h\xcb1R3l\xc0\x953\x81&f\x88Gbranch2\x81T"Aa\xc7X\x9a\xa4\x8f\xa8:H\xfe\xff^\x95\xb5j\xe3\'\xfcGdefault\x82T&\x80Z\xba\x1e`\n
+  s>     \x82\xe96a\x14\x9f#\x13\x86j"\x1a{T\xbe\x0e\xf7<\x17\xad\xe3\xfc\x89\xdcAp\x1e\xb9\xfc:\x91\xb5\x82\x82
+  s>     \r\n
+  received frame(size=112; request=1; stream=2; streamflags=stream-begin; type=bytes-response; flags=eos|cbor)
+  s>     0\r\n
+  s>     \r\n
+  response: [{b'branch1': [b'\xb5\xfa\xac\xdf\xd2c7h\xcb1R3l\xc0\x953\x81&f\x88'], b'branch2': [b'"Aa\xc7X\x9a\xa4\x8f\xa8:H\xfe\xff^\x95\xb5j\xe3\'\xfc'], b'default': [b'&\x80Z\xba\x1e`\n\x82\xe96a\x14\x9f#\x13\x86j"\x1a{', b'\xbe\x0e\xf7<\x17\xad\xe3\xfc\x89\xdcAp\x1e\xb9\xfc:\x91\xb5\x82\x82']}]
+
+  $ cat error.log