diff --git a/.vscode/tasks.json b/.vscode/tasks.json
index d1d41bc..b18827c 100644
--- a/.vscode/tasks.json
+++ b/.vscode/tasks.json
@@ -2,7 +2,7 @@
     // See https://go.microsoft.com/fwlink/?LinkId=733558
     // for the documentation about the tasks.json format
     "version": "0.1.0",
-    "command": "proto3fmt",
+    "command": "protofmt",
     "isShellCommand": true,
     "args": ["${file}"],
     "showOutput": "always"
diff --git a/README.md b/README.md
index f8e80db..4f7a6db 100644
--- a/README.md
+++ b/README.md
@@ -1,20 +1,20 @@
-# proto3
+# proto
 
-[![Build Status](https://travis-ci.org/emicklei/proto3.png)](https://travis-ci.org/emicklei/proto3)
-[![GoDoc](https://godoc.org/github.com/emicklei/proto3?status.svg)](https://godoc.org/github.com/emicklei/proto3)
+[![Build Status](https://travis-ci.org/emicklei/proto.png)](https://travis-ci.org/emicklei/proto)
+[![GoDoc](https://godoc.org/github.com/emicklei/proto?status.svg)](https://godoc.org/github.com/emicklei/proto)
 
-Package in Go for parsing Google Protocol Buffers [.proto files version 3] (https://developers.google.com/protocol-buffers/docs/reference/proto3-spec)
+Package in Go for parsing Google Protocol Buffers [.proto files version 3] (https://developers.google.com/protocol-buffers/docs/reference/proto-spec)
 
 ### usage
 
-    parser := proto3.NewParser(anIOReader)
+    parser := proto.NewParser(anIOReader)
 	proto, err := parser.Parse()
 	if err != nil {
-		log.Fatalln("proto3 parsing failed", err)
+		log.Fatalln("proto parsing failed", err)
 	}
 
 ### install
 
-    go get -u -v github.com/emicklei/proto3
+    go get -u -v github.com/emicklei/proto
 
 © 2017, ernestmicklei.com.  MIT License. Contributions welcome.
\ No newline at end of file
diff --git a/cmd/proto3fmt/formatter.go b/cmd/protofmt/formatter.go
similarity index 81%
rename from cmd/proto3fmt/formatter.go
rename to cmd/protofmt/formatter.go
index 7ae0314..bf91fce 100644
--- a/cmd/proto3fmt/formatter.go
+++ b/cmd/protofmt/formatter.go
@@ -6,7 +6,7 @@ import (
 
 	"strings"
 
-	"github.com/emicklei/proto3"
+	"github.com/emicklei/proto"
 )
 
 type formatter struct {
@@ -16,7 +16,7 @@ type formatter struct {
 	indentSeparator string
 }
 
-func (f *formatter) VisitComment(c *proto3.Comment) {
+func (f *formatter) VisitComment(c *proto.Comment) {
 	f.begin("comment")
 	if c.IsMultiline() {
 		fmt.Fprintln(f.w, "/*")
@@ -27,7 +27,7 @@ func (f *formatter) VisitComment(c *proto3.Comment) {
 	}
 }
 
-func (f *formatter) VisitEnum(e *proto3.Enum) {
+func (f *formatter) VisitEnum(e *proto.Enum) {
 	f.begin("enum")
 	fmt.Fprintf(f.w, "enum %s {", e.Name)
 	f.indentLevel++
@@ -38,7 +38,7 @@ func (f *formatter) VisitEnum(e *proto3.Enum) {
 	io.WriteString(f.w, "}\n")
 }
 
-func (f *formatter) VisitEnumField(e *proto3.EnumField) {
+func (f *formatter) VisitEnumField(e *proto.EnumField) {
 	f.begin("field")
 	io.WriteString(f.w, paddedTo(e.Name, 10))
 	fmt.Fprintf(f.w, " = %d", e.Integer)
@@ -50,7 +50,7 @@ func (f *formatter) VisitEnumField(e *proto3.EnumField) {
 	}
 }
 
-func (f *formatter) VisitImport(i *proto3.Import) {
+func (f *formatter) VisitImport(i *proto.Import) {
 	f.begin("import")
 	if len(i.Kind) > 0 {
 		fmt.Fprintf(f.w, "import %s ", i.Kind)
@@ -58,7 +58,7 @@ func (f *formatter) VisitImport(i *proto3.Import) {
 	fmt.Fprintf(f.w, "import %q;\n", i.Filename)
 }
 
-func (f *formatter) VisitMessage(m *proto3.Message) {
+func (f *formatter) VisitMessage(m *proto.Message) {
 	f.begin("message")
 	fmt.Fprintf(f.w, "message %s {", m.Name)
 	f.newLineIf(len(m.Elements) > 0)
@@ -70,7 +70,7 @@ func (f *formatter) VisitMessage(m *proto3.Message) {
 	io.WriteString(f.w, "}\n")
 }
 
-func (f *formatter) VisitOption(o *proto3.Option) {
+func (f *formatter) VisitOption(o *proto.Option) {
 	if o.IsEmbedded {
 		io.WriteString(f.w, "[(")
 	} else {
@@ -92,12 +92,12 @@ func (f *formatter) VisitOption(o *proto3.Option) {
 	}
 }
 
-func (f *formatter) VisitPackage(p *proto3.Package) {
+func (f *formatter) VisitPackage(p *proto.Package) {
 	f.begin("package")
 	fmt.Fprintf(f.w, "package %s;\n", p.Name)
 }
 
-func (f *formatter) VisitService(s *proto3.Service) {
+func (f *formatter) VisitService(s *proto.Service) {
 	f.begin("service")
 	fmt.Fprintf(f.w, "service %s {", s.Name)
 	f.indentLevel++
@@ -108,11 +108,11 @@ func (f *formatter) VisitService(s *proto3.Service) {
 	io.WriteString(f.w, "}\n")
 }
 
-func (f *formatter) VisitSyntax(s *proto3.Syntax) {
+func (f *formatter) VisitSyntax(s *proto.Syntax) {
 	fmt.Fprintf(f.w, "syntax = %q;\n\n", s.Value)
 }
 
-func (f *formatter) VisitOneof(o *proto3.Oneof) {
+func (f *formatter) VisitOneof(o *proto.Oneof) {
 	f.begin("oneof")
 	fmt.Fprintf(f.w, "oneof %s {", o.Name)
 	f.indentLevel++
@@ -123,7 +123,7 @@ func (f *formatter) VisitOneof(o *proto3.Oneof) {
 	io.WriteString(f.w, "}\n")
 }
 
-func (f *formatter) VisitOneofField(o *proto3.OneOfField) {
+func (f *formatter) VisitOneofField(o *proto.OneOfField) {
 	f.begin("oneoffield")
 	fmt.Fprintf(f.w, "%s %s = %d", o.Type, o.Name, o.Sequence)
 	for _, each := range o.Options {
@@ -132,7 +132,7 @@ func (f *formatter) VisitOneofField(o *proto3.OneOfField) {
 	io.WriteString(f.w, ";\n")
 }
 
-func (f *formatter) VisitReserved(r *proto3.Reserved) {
+func (f *formatter) VisitReserved(r *proto.Reserved) {
 	f.begin("reserved")
 	io.WriteString(f.w, "reserved")
 	if len(r.Ranges) > 0 {
@@ -148,7 +148,7 @@ func (f *formatter) VisitReserved(r *proto3.Reserved) {
 	io.WriteString(f.w, ";\n")
 }
 
-func (f *formatter) VisitRPC(r *proto3.RPC) {
+func (f *formatter) VisitRPC(r *proto.RPC) {
 	f.begin("rpc")
 	fmt.Fprintf(f.w, "rpc %s (", r.Name)
 	if r.StreamsRequest {
@@ -163,12 +163,12 @@ func (f *formatter) VisitRPC(r *proto3.RPC) {
 	io.WriteString(f.w, ");\n")
 }
 
-func (f *formatter) VisitMapField(m *proto3.MapField) {
+func (f *formatter) VisitMapField(m *proto.MapField) {
 	f.begin("map")
 	fmt.Fprintf(f.w, "map<%s,%s> %s = %d;\n", m.KeyType, m.Type, m.Name, m.Sequence)
 }
 
-func (f *formatter) VisitNormalField(f1 *proto3.NormalField) {
+func (f *formatter) VisitNormalField(f1 *proto.NormalField) {
 	f.begin("field")
 	if f1.Repeated {
 		io.WriteString(f.w, "repeated ")
diff --git a/cmd/proto3fmt/main.go b/cmd/protofmt/main.go
similarity index 62%
rename from cmd/proto3fmt/main.go
rename to cmd/protofmt/main.go
index 510db9c..8cf7732 100644
--- a/cmd/proto3fmt/main.go
+++ b/cmd/protofmt/main.go
@@ -4,24 +4,23 @@ import (
 	"log"
 	"os"
 
-	"github.com/emicklei/proto3"
+	"github.com/emicklei/proto"
 )
 
-// go run *.go example1.proto
-// go run *.go example0.proto
+// go run *.go unformatted.proto
 func main() {
 	if len(os.Args) == 1 {
-		log.Fatal("Usage: proto3fmt my.proto")
+		log.Fatal("Usage: protofmt my.proto")
 	}
 	i, err := os.Open(os.Args[1])
 	if err != nil {
 		log.Fatal(err)
 	}
 	defer i.Close()
-	p := proto3.NewParser(i)
+	p := proto.NewParser(i)
 	def, err := p.Parse()
 	if err != nil {
-		log.Fatalln("proto3fmt failed", err)
+		log.Fatalln("protofmt failed", err)
 	}
 	f := &formatter{w: os.Stdout, indentSeparator: "  "}
 	for _, each := range def.Elements {
diff --git a/cmd/proto3fmt/unformatted.proto b/cmd/protofmt/unformatted.proto
similarity index 95%
rename from cmd/proto3fmt/unformatted.proto
rename to cmd/protofmt/unformatted.proto
index 38d997a..de67d42 100644
--- a/cmd/proto3fmt/unformatted.proto
+++ b/cmd/protofmt/unformatted.proto
@@ -13,7 +13,7 @@ import public    "testdata/test.proto";
 
 /* This pkg
         */
-package         here.proto3_proto   ;
+package         here.proto_proto   ;
 
 
 // from a bottle
diff --git a/cmd/proto3fmt/unittest_proto3.proto b/cmd/protofmt/unittest_proto3.proto
similarity index 98%
rename from cmd/proto3fmt/unittest_proto3.proto
rename to cmd/protofmt/unittest_proto3.proto
index b539118..dce37be 100644
--- a/cmd/proto3fmt/unittest_proto3.proto
+++ b/cmd/protofmt/unittest_proto3.proto
@@ -34,7 +34,7 @@
 //
 // A proto file we will use for unit testing.
 
-syntax = "proto3";
+syntax = "proto";
 
 // Some generic_services option(s) added automatically.
 // See:  http://go/proto2-generic-services-default
@@ -44,7 +44,7 @@ option py_generic_services = true;     // auto-added
 option cc_enable_arenas = true;
 option csharp_namespace = "Google.Protobuf.TestProtos";
 
-import "google/protobuf/unittest_import_proto3.proto";
+import "google/protobuf/unittest_import_proto.proto";
 
 // We don't put this in a package within proto2 because we need to make sure
 // that the generated code doesn't depend on being in the proto2 namespace.
@@ -221,7 +221,7 @@ enum TestSparseEnum {
   SPARSE_C = 12589234;
   SPARSE_D = -15;
   SPARSE_E = -53452;
-  // In proto3, value 0 must be the first one specified
+  // In proto, value 0 must be the first one specified
   // SPARSE_F = 0;
   SPARSE_G = 2;
 }
diff --git a/cmd/proto3fmt/unittest_proto3_arena.proto b/cmd/protofmt/unittest_proto3_arena.proto
similarity index 98%
rename from cmd/proto3fmt/unittest_proto3_arena.proto
rename to cmd/protofmt/unittest_proto3_arena.proto
index edae8c8..9dc31ae 100644
--- a/cmd/proto3fmt/unittest_proto3_arena.proto
+++ b/cmd/protofmt/unittest_proto3_arena.proto
@@ -28,13 +28,13 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-syntax = "proto3";
+syntax = "proto";
 
 option cc_enable_arenas = true;
 
 import "google/protobuf/unittest_import.proto";
 
-package proto3_arena_unittest;
+package proto_arena_unittest;
 
 // This proto includes every type of field in both singular and repeated
 // forms.
@@ -71,7 +71,7 @@ message TestAllTypes {
     string optional_string   = 14;
      bytes optional_bytes    = 15;
 
-  // Groups are not allowed in proto3.
+  // Groups are not allowed in proto.
   // optional group OptionalGroup = 16 {
   //   optional int32 a = 17;
   // }
@@ -114,7 +114,7 @@ message TestAllTypes {
   repeated   string repeated_string   = 44;
   repeated    bytes repeated_bytes    = 45;
 
-  // Groups are not allowed in proto3.
+  // Groups are not allowed in proto.
   // repeated group RepeatedGroup = 46 {
   //   optional int32 a = 47;
   // }
diff --git a/enum.go b/enum.go
index b92f998..5af47ef 100644
--- a/enum.go
+++ b/enum.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import "fmt"
 
diff --git a/enum_test.go b/enum_test.go
index 64966ac..844004c 100644
--- a/enum_test.go
+++ b/enum_test.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import "testing"
 
diff --git a/field.go b/field.go
index fb234f5..73599ce 100644
--- a/field.go
+++ b/field.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 // Field is an abstract message field.
 type Field struct {
diff --git a/field_test.go b/field_test.go
index 5e1cbc7..d745dfe 100644
--- a/field_test.go
+++ b/field_test.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import "testing"
 
diff --git a/import.go b/import.go
index 0e0e900..d5c60f6 100644
--- a/import.go
+++ b/import.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 // Import holds a filename to another .proto definition.
 type Import struct {
diff --git a/import_test.go b/import_test.go
index cf4aada..efb0f7b 100644
--- a/import_test.go
+++ b/import_test.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import "testing"
 
diff --git a/message.go b/message.go
index 491a3ed..4db62d6 100644
--- a/message.go
+++ b/message.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 // Message consists of a message name and a message body.
 type Message struct {
diff --git a/message_test.go b/message_test.go
index 3c414c5..4257efe 100644
--- a/message_test.go
+++ b/message_test.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import "testing"
 
diff --git a/oneof.go b/oneof.go
index 0ef4fb4..53a0d9a 100644
--- a/oneof.go
+++ b/oneof.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import (
 	"fmt"
diff --git a/oneof_test.go b/oneof_test.go
index 7321bc4..208dc9e 100644
--- a/oneof_test.go
+++ b/oneof_test.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import "testing"
 
diff --git a/option.go b/option.go
index 0799f02..3866113 100644
--- a/option.go
+++ b/option.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import "fmt"
 
diff --git a/option_test.go b/option_test.go
index 4116947..16f4aff 100644
--- a/option_test.go
+++ b/option_test.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import "testing"
 
diff --git a/package.go b/package.go
index d9ea315..111caf1 100644
--- a/package.go
+++ b/package.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import "fmt"
 
diff --git a/parser.go b/parser.go
index 1bfa5ad..69f3d77 100644
--- a/parser.go
+++ b/parser.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import (
 	"fmt"
diff --git a/parser_test.go b/parser_test.go
index 43b7af4..e5b1b51 100644
--- a/parser_test.go
+++ b/parser_test.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import (
 	"strings"
diff --git a/proto.go b/proto.go
index 0ea1b0a..9984da5 100644
--- a/proto.go
+++ b/proto.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import (
 	"log"
diff --git a/proto_test.go b/proto_test.go
index 7b182f1..7d60564 100644
--- a/proto_test.go
+++ b/proto_test.go
@@ -1,9 +1,9 @@
-package proto3
+package proto
 
 import "testing"
 
 const example = `
-syntax = “proto3”;
+syntax = “proto”;
 import public “other.proto”;
 option java_package = "com.example.foo";
 enum EnumAllowingAlias {
diff --git a/reserved.go b/reserved.go
index 5da297a..0f89c3f 100644
--- a/reserved.go
+++ b/reserved.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import (
 	"fmt"
diff --git a/reserved_test.go b/reserved_test.go
index f059313..e7b0dd3 100644
--- a/reserved_test.go
+++ b/reserved_test.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import "testing"
 
diff --git a/scanner.go b/scanner.go
index 8068bbb..c14de94 100644
--- a/scanner.go
+++ b/scanner.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 // partial code from https://raw.githubusercontent.com/benbjohnson/sql-parser/master/scanner.go
 
diff --git a/scanner_test.go b/scanner_test.go
index 3a4c32c..df80745 100644
--- a/scanner_test.go
+++ b/scanner_test.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import (
 	"strings"
diff --git a/service.go b/service.go
index 39b4c16..bc34493 100644
--- a/service.go
+++ b/service.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 // Service defines a set of RPC calls.
 type Service struct {
diff --git a/service_test.go b/service_test.go
index 98acbd2..5ba9ed5 100644
--- a/service_test.go
+++ b/service_test.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import "testing"
 
diff --git a/syntax.go b/syntax.go
index d48c2e5..6eca510 100644
--- a/syntax.go
+++ b/syntax.go
@@ -1,6 +1,6 @@
-package proto3
+package proto
 
-// Syntax should have value "proto3"
+// Syntax should have value "proto"
 type Syntax struct {
 	Value string
 }
@@ -19,7 +19,7 @@ func (s *Syntax) parse(p *Parser) error {
 	}
 	tok, lit := p.scanIgnoreWhitespace()
 	if tok != tIDENT {
-		return p.unexpected(lit, "proto3")
+		return p.unexpected(lit, "proto")
 	}
 	if tok, lit := p.scanIgnoreWhitespace(); tok != tQUOTE && tok != tSINGLEQUOTE {
 		return p.unexpected(lit, "\" or '")
diff --git a/syntax_test.go b/syntax_test.go
index bdc0c05..c1c4d31 100644
--- a/syntax_test.go
+++ b/syntax_test.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 import (
 	"strconv"
@@ -6,7 +6,7 @@ import (
 )
 
 func TestSyntax(t *testing.T) {
-	proto := `syntax = "proto3";`
+	proto := `syntax = "proto";`
 	p := newParserOn(proto)
 	p.scanIgnoreWhitespace() // consume first token
 	s := new(Syntax)
@@ -14,7 +14,7 @@ func TestSyntax(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if got, want := s.Value, "proto3"; got != want {
+	if got, want := s.Value, "proto"; got != want {
 		t.Errorf("got [%v] want [%v]", got, want)
 	}
 }
@@ -23,7 +23,7 @@ func TestCommentAroundSyntax(t *testing.T) {
 	proto := `
 	// comment1
 	// comment2
-	syntax = 'proto3'; // comment3
+	syntax = 'proto'; // comment3
 	// comment4
 `
 	p := newParserOn(proto)
diff --git a/token.go b/token.go
index 431698d..b80bd12 100644
--- a/token.go
+++ b/token.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 // token represents a lexical token.
 type token int
diff --git a/visitor.go b/visitor.go
index f89d41b..f8c3ef7 100644
--- a/visitor.go
+++ b/visitor.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 // Visitor is for dispatching Proto elements.
 type Visitor interface {
diff --git a/visitor_test.go b/visitor_test.go
index a26e069..9bab848 100644
--- a/visitor_test.go
+++ b/visitor_test.go
@@ -1,4 +1,4 @@
-package proto3
+package proto
 
 type collector struct {
 	proto *Proto