diff --git a/types/proto3/block.pb.go b/types/proto3/block.pb.go
new file mode 100644
index 000000000..96d5d34f8
--- /dev/null
+++ b/types/proto3/block.pb.go
@@ -0,0 +1,257 @@
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// source: block.proto
+
+/*
+Package proto3 is a generated protocol buffer package.
+
+It is generated from these files:
+	block.proto
+
+It has these top-level messages:
+	PartSetHeader
+	BlockID
+	Header
+	Timestamp
+*/
+package proto3
+
+import proto "github.com/golang/protobuf/proto"
+import fmt "fmt"
+import math "math"
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion2 // please upgrade the proto package
+
+type PartSetHeader struct {
+	Total int32  `protobuf:"zigzag32,1,opt,name=Total" json:"Total,omitempty"`
+	Hash  []byte `protobuf:"bytes,2,opt,name=Hash,proto3" json:"Hash,omitempty"`
+}
+
+func (m *PartSetHeader) Reset()                    { *m = PartSetHeader{} }
+func (m *PartSetHeader) String() string            { return proto.CompactTextString(m) }
+func (*PartSetHeader) ProtoMessage()               {}
+func (*PartSetHeader) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{0} }
+
+func (m *PartSetHeader) GetTotal() int32 {
+	if m != nil {
+		return m.Total
+	}
+	return 0
+}
+
+func (m *PartSetHeader) GetHash() []byte {
+	if m != nil {
+		return m.Hash
+	}
+	return nil
+}
+
+type BlockID struct {
+	Hash        []byte         `protobuf:"bytes,1,opt,name=Hash,proto3" json:"Hash,omitempty"`
+	PartsHeader *PartSetHeader `protobuf:"bytes,2,opt,name=PartsHeader" json:"PartsHeader,omitempty"`
+}
+
+func (m *BlockID) Reset()                    { *m = BlockID{} }
+func (m *BlockID) String() string            { return proto.CompactTextString(m) }
+func (*BlockID) ProtoMessage()               {}
+func (*BlockID) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{1} }
+
+func (m *BlockID) GetHash() []byte {
+	if m != nil {
+		return m.Hash
+	}
+	return nil
+}
+
+func (m *BlockID) GetPartsHeader() *PartSetHeader {
+	if m != nil {
+		return m.PartsHeader
+	}
+	return nil
+}
+
+type Header struct {
+	// basic block info
+	ChainID string     `protobuf:"bytes,1,opt,name=ChainID" json:"ChainID,omitempty"`
+	Height  int64      `protobuf:"zigzag64,2,opt,name=Height" json:"Height,omitempty"`
+	Time    *Timestamp `protobuf:"bytes,3,opt,name=Time" json:"Time,omitempty"`
+	NumTxs  int64      `protobuf:"zigzag64,4,opt,name=NumTxs" json:"NumTxs,omitempty"`
+	// prev block info
+	LastBlockID *BlockID `protobuf:"bytes,5,opt,name=LastBlockID" json:"LastBlockID,omitempty"`
+	TotalTxs    int64    `protobuf:"zigzag64,6,opt,name=TotalTxs" json:"TotalTxs,omitempty"`
+	// hashes of block data
+	LastCommitHash []byte `protobuf:"bytes,7,opt,name=LastCommitHash,proto3" json:"LastCommitHash,omitempty"`
+	DataHash       []byte `protobuf:"bytes,8,opt,name=DataHash,proto3" json:"DataHash,omitempty"`
+	// hashes from the app output from the prev block
+	ValidatorsHash  []byte `protobuf:"bytes,9,opt,name=ValidatorsHash,proto3" json:"ValidatorsHash,omitempty"`
+	ConsensusHash   []byte `protobuf:"bytes,10,opt,name=ConsensusHash,proto3" json:"ConsensusHash,omitempty"`
+	AppHash         []byte `protobuf:"bytes,11,opt,name=AppHash,proto3" json:"AppHash,omitempty"`
+	LastResultsHash []byte `protobuf:"bytes,12,opt,name=LastResultsHash,proto3" json:"LastResultsHash,omitempty"`
+	// consensus info
+	EvidenceHash []byte `protobuf:"bytes,13,opt,name=EvidenceHash,proto3" json:"EvidenceHash,omitempty"`
+}
+
+func (m *Header) Reset()                    { *m = Header{} }
+func (m *Header) String() string            { return proto.CompactTextString(m) }
+func (*Header) ProtoMessage()               {}
+func (*Header) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{2} }
+
+func (m *Header) GetChainID() string {
+	if m != nil {
+		return m.ChainID
+	}
+	return ""
+}
+
+func (m *Header) GetHeight() int64 {
+	if m != nil {
+		return m.Height
+	}
+	return 0
+}
+
+func (m *Header) GetTime() *Timestamp {
+	if m != nil {
+		return m.Time
+	}
+	return nil
+}
+
+func (m *Header) GetNumTxs() int64 {
+	if m != nil {
+		return m.NumTxs
+	}
+	return 0
+}
+
+func (m *Header) GetLastBlockID() *BlockID {
+	if m != nil {
+		return m.LastBlockID
+	}
+	return nil
+}
+
+func (m *Header) GetTotalTxs() int64 {
+	if m != nil {
+		return m.TotalTxs
+	}
+	return 0
+}
+
+func (m *Header) GetLastCommitHash() []byte {
+	if m != nil {
+		return m.LastCommitHash
+	}
+	return nil
+}
+
+func (m *Header) GetDataHash() []byte {
+	if m != nil {
+		return m.DataHash
+	}
+	return nil
+}
+
+func (m *Header) GetValidatorsHash() []byte {
+	if m != nil {
+		return m.ValidatorsHash
+	}
+	return nil
+}
+
+func (m *Header) GetConsensusHash() []byte {
+	if m != nil {
+		return m.ConsensusHash
+	}
+	return nil
+}
+
+func (m *Header) GetAppHash() []byte {
+	if m != nil {
+		return m.AppHash
+	}
+	return nil
+}
+
+func (m *Header) GetLastResultsHash() []byte {
+	if m != nil {
+		return m.LastResultsHash
+	}
+	return nil
+}
+
+func (m *Header) GetEvidenceHash() []byte {
+	if m != nil {
+		return m.EvidenceHash
+	}
+	return nil
+}
+
+type Timestamp struct {
+	Seconds int64 `protobuf:"fixed64,1,opt,name=seconds" json:"seconds,omitempty"`
+	Nanos   int32 `protobuf:"fixed32,2,opt,name=nanos" json:"nanos,omitempty"`
+}
+
+func (m *Timestamp) Reset()                    { *m = Timestamp{} }
+func (m *Timestamp) String() string            { return proto.CompactTextString(m) }
+func (*Timestamp) ProtoMessage()               {}
+func (*Timestamp) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{3} }
+
+func (m *Timestamp) GetSeconds() int64 {
+	if m != nil {
+		return m.Seconds
+	}
+	return 0
+}
+
+func (m *Timestamp) GetNanos() int32 {
+	if m != nil {
+		return m.Nanos
+	}
+	return 0
+}
+
+func init() {
+	proto.RegisterType((*PartSetHeader)(nil), "proto3.PartSetHeader")
+	proto.RegisterType((*BlockID)(nil), "proto3.BlockID")
+	proto.RegisterType((*Header)(nil), "proto3.Header")
+	proto.RegisterType((*Timestamp)(nil), "proto3.Timestamp")
+}
+
+func init() { proto.RegisterFile("block.proto", fileDescriptor0) }
+
+var fileDescriptor0 = []byte{
+	// 372 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x5c, 0x92, 0x4f, 0x6b, 0xe3, 0x30,
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+	0xde, 0x9b, 0x37, 0xbf, 0x91, 0x47, 0x02, 0x7f, 0x9b, 0xa8, 0xdd, 0xfb, 0x34, 0xcb, 0x95, 0x51,
+	0xd8, 0xa6, 0x9f, 0x59, 0x78, 0x0b, 0x83, 0x17, 0x9e, 0x9b, 0x57, 0x61, 0x96, 0x82, 0x47, 0x22,
+	0xc7, 0xbf, 0xd0, 0x5a, 0x2b, 0xc3, 0x93, 0xc0, 0x1b, 0x7b, 0x93, 0x11, 0x73, 0x02, 0x11, 0x9a,
+	0x4b, 0xae, 0xf7, 0xc1, 0xaf, 0xb1, 0x37, 0xe9, 0x33, 0xfa, 0x1f, 0x6e, 0xa0, 0xf3, 0x60, 0x89,
+	0xab, 0x45, 0x55, 0xf6, 0x7e, 0xca, 0x78, 0x03, 0xbe, 0x25, 0x6b, 0xc7, 0xa5, 0x4e, 0xff, 0xfa,
+	0x9f, 0x1b, 0x3f, 0x9b, 0xd6, 0x86, 0xb2, 0xe3, 0x64, 0xf8, 0xd5, 0x80, 0x76, 0x71, 0x98, 0x00,
+	0x3a, 0xf3, 0x3d, 0x8f, 0xe5, 0x6a, 0x41, 0xe8, 0x1e, 0x2b, 0x25, 0xfe, 0xb7, 0x99, 0xf8, 0x6d,
+	0x6f, 0x08, 0x8c, 0xac, 0x50, 0x78, 0x01, 0xcd, 0x75, 0x9c, 0x8a, 0xa0, 0x41, 0xe3, 0x46, 0xe5,
+	0x38, 0xeb, 0x69, 0xc3, 0xd3, 0x8c, 0x51, 0xd9, 0xb6, 0x3f, 0x1f, 0xd2, 0xf5, 0xa7, 0x0e, 0x9a,
+	0xae, 0xdd, 0x29, 0xbc, 0x02, 0xff, 0x89, 0x6b, 0x53, 0x7c, 0x57, 0xd0, 0x22, 0xca, 0xb0, 0xa4,
+	0x14, 0x36, 0x3b, 0xce, 0xe0, 0x19, 0x74, 0x69, 0x47, 0x16, 0xd6, 0x26, 0x58, 0xa5, 0xf1, 0x12,
+	0x7e, 0xdb, 0xe8, 0x5c, 0xa5, 0x69, 0x6c, 0x68, 0x43, 0x1d, 0xda, 0xd0, 0x89, 0x6b, 0x19, 0x0b,
+	0x6e, 0x38, 0x25, 0xba, 0x94, 0xa8, 0xb4, 0x65, 0x6c, 0x78, 0x12, 0x47, 0xdc, 0xa8, 0x5c, 0x53,
+	0xa2, 0xe7, 0x18, 0x75, 0x17, 0xcf, 0x61, 0x30, 0x57, 0x52, 0x0b, 0xa9, 0x0f, 0x2e, 0x06, 0x14,
+	0xab, 0x9b, 0x76, 0xa3, 0xf7, 0x59, 0x46, 0x75, 0x9f, 0xea, 0xa5, 0xc4, 0x09, 0x0c, 0xed, 0xa9,
+	0x98, 0xd0, 0x87, 0xc4, 0x38, 0x42, 0x9f, 0x12, 0xa7, 0x36, 0x86, 0xd0, 0x7f, 0xfc, 0x88, 0x23,
+	0x21, 0x77, 0x82, 0x62, 0x03, 0x8a, 0xd5, 0xbc, 0xf0, 0x0e, 0x7a, 0xd5, 0xce, 0xed, 0x50, 0x2d,
+	0x76, 0x4a, 0x46, 0x9a, 0xae, 0xf1, 0x0f, 0x2b, 0xa5, 0x7d, 0x6d, 0x92, 0x4b, 0xa5, 0xe9, 0x16,
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+	0xb2, 0x02, 0x00, 0x00,
+}
diff --git a/types/proto3_test.go b/types/proto3_test.go
index e06341821..0ab14ea3a 100644
--- a/types/proto3_test.go
+++ b/types/proto3_test.go
@@ -61,6 +61,7 @@ func TestProto3Compatibility(t *testing.T) {
 		Height:150,
 		Time: &proto3.Timestamp{Seconds:seconds, Nanos:nanos},
 		NumTxs: 7,
+		// TODO(ismail): as Jae suggested, we'll add a flag to make this obsolete:
 		LastBlockID: &proto3.BlockID{
 			PartsHeader: &proto3.PartSetHeader{},
 		},