diff --git a/chat_test.go b/chat_test.go
index 524439520..7a549fa90 100644
--- a/chat_test.go
+++ b/chat_test.go
@@ -82,6 +82,14 @@ func TestPostMessage(t *testing.T) {
 	blockStr := `[{"type":"context","block_id":"context","elements":[{"type":"plain_text","text":"hello"}]}]`
 
 	tests := map[string]messageTest{
+		"OnlyBasicProperties": {
+			endpoint: "/chat.postMessage",
+			opt:      []MsgOption{},
+			expected: url.Values{
+				"channel": []string{"CXXX"},
+				"token":   []string{"testing-token"},
+			},
+		},
 		"Blocks": {
 			endpoint: "/chat.postMessage",
 			opt: []MsgOption{
diff --git a/conversation.go b/conversation.go
index 299362601..e523716cc 100644
--- a/conversation.go
+++ b/conversation.go
@@ -571,12 +571,13 @@ func (api *Client) JoinConversationContext(ctx context.Context, channelID string
 }
 
 type GetConversationHistoryParameters struct {
-	ChannelID string
-	Cursor    string
-	Inclusive bool
-	Latest    string
-	Limit     int
-	Oldest    string
+	ChannelID          string
+	Cursor             string
+	Inclusive          bool
+	Latest             string
+	Limit              int
+	Oldest             string
+	IncludeAllMetadata bool
 }
 
 type GetConversationHistoryResponse struct {
@@ -615,6 +616,11 @@ func (api *Client) GetConversationHistoryContext(ctx context.Context, params *Ge
 	if params.Oldest != "" {
 		values.Add("oldest", params.Oldest)
 	}
+	if params.IncludeAllMetadata {
+		values.Add("include_all_metadata", "1")
+	} else {
+		values.Add("include_all_metadata", "0")
+	}
 
 	response := GetConversationHistoryResponse{}
 
diff --git a/messages.go b/messages.go
index 828fa6026..333404563 100644
--- a/messages.go
+++ b/messages.go
@@ -129,7 +129,7 @@ type Msg struct {
 	ReplaceOriginal bool   `json:"replace_original"`
 	DeleteOriginal  bool   `json:"delete_original"`
 
-	// Block type Message
+	// metadata
 	Metadata SlackMetadata `json:"metadata,omitempty"`
 
 	// Block type Message