diff --git a/runtime/syntax/proto.vim b/runtime/syntax/proto.vim
index 4615e0c..0d2d2f2 100644
--- a/runtime/syntax/proto.vim
+++ b/runtime/syntax/proto.vim
@@ -1,26 +1,36 @@
-" syntax file for Protocol Buffers - Google's data interchange format
-"
+" Protocol Buffers - Google's data interchange format
 " Copyright 2008 Google Inc.  All rights reserved.
+" https://developers.google.com/protocol-buffers/
 "
-" Permission is hereby granted, free of charge, to any person obtaining a copy
-" of this software and associated documentation files (the "Software"), to deal
-" in the Software without restriction, including without limitation the rights
-" to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-" copies of the Software, and to permit persons to whom the Software is
-" furnished to do so, subject to the following conditions:
+" Redistribution and use in source and binary forms, with or without
+" modification, are permitted provided that the following conditions are
+" met:
 "
-" The above copyright notice and this permission notice shall be included in
-" all copies or substantial portions of the Software.
+"     * Redistributions of source code must retain the above copyright
+" notice, this list of conditions and the following disclaimer.
+"     * Redistributions in binary form must reproduce the above
+" copyright notice, this list of conditions and the following disclaimer
+" in the documentation and/or other materials provided with the
+" distribution.
+"     * Neither the name of Google Inc. nor the names of its
+" contributors may be used to endorse or promote products derived from
+" this software without specific prior written permission.
 "
-" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-" IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-" FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-" AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-" LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-" OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-" THE SOFTWARE.
-"
-" http://code.google.com/p/protobuf/
+" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+" "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+" LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+" A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+" OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+" LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+" OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+" This is the Vim syntax file for Google Protocol Buffers as found at
+" https://github.com/protocolbuffers/protobuf
+" Last update: 2020 Oct 29
 
 " quit when a syntax file was already loaded
 if exists("b:current_syntax")
@@ -33,10 +43,10 @@
 syn cluster protoCommentGrp contains=protoTodo
 
 syn keyword protoSyntax     syntax import option
-syn keyword protoStructure  package message group
+syn keyword protoStructure  package message group oneof
 syn keyword protoRepeat     optional required repeated
 syn keyword protoDefault    default
-syn keyword protoExtend     extend extensions to max
+syn keyword protoExtend     extend extensions to max reserved
 syn keyword protoRPC        service rpc returns
 
 syn keyword protoType      int32 int64 uint32 uint64 sint32 sint64
@@ -48,10 +58,10 @@
 syn match   protoInt     /-\?\<\d\+\>/
 syn match   protoInt     /\<0[xX]\x+\>/
 syn match   protoFloat   /\<-\?\d*\(\.\d*\)\?/
-syn region  protoComment start="\/\*" end="\*\/" contains=@protoCommentGrp
-syn region  protoComment start="//" skip="\\$" end="$" keepend contains=@protoCommentGrp
-syn region  protoString  start=/"/ skip=/\\./ end=/"/
-syn region  protoString  start=/'/ skip=/\\./ end=/'/
+syn region  protoComment start="\/\*" end="\*\/" contains=@pbCommentGrp,@Spell
+syn region  protoComment start="//" skip="\\$" end="$" keepend contains=@pbCommentGrp,@Spell
+syn region  protoString  start=/"/ skip=/\\./ end=/"/ contains=@Spell
+syn region  protoString  start=/'/ skip=/\\./ end=/'/ contains=@Spell
 
 hi def link protoTodo         Todo