diff --git a/assistant.go b/assistant.go
index 9415325f..661681e8 100644
--- a/assistant.go
+++ b/assistant.go
@@ -11,7 +11,6 @@ import (
 const (
 	assistantsSuffix      = "/assistants"
 	assistantsFilesSuffix = "/files"
-	openaiAssistantsV1    = "assistants=v1"
 )
 
 type Assistant struct {
@@ -116,7 +115,7 @@ type AssistantFilesList struct {
 // CreateAssistant creates a new assistant.
 func (c *Client) CreateAssistant(ctx context.Context, request AssistantRequest) (response Assistant, err error) {
 	req, err := c.newRequest(ctx, http.MethodPost, c.fullURL(assistantsSuffix), withBody(request),
-		withBetaAssistantV1())
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -132,7 +131,7 @@ func (c *Client) RetrieveAssistant(
 ) (response Assistant, err error) {
 	urlSuffix := fmt.Sprintf("%s/%s", assistantsSuffix, assistantID)
 	req, err := c.newRequest(ctx, http.MethodGet, c.fullURL(urlSuffix),
-		withBetaAssistantV1())
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -149,7 +148,7 @@ func (c *Client) ModifyAssistant(
 ) (response Assistant, err error) {
 	urlSuffix := fmt.Sprintf("%s/%s", assistantsSuffix, assistantID)
 	req, err := c.newRequest(ctx, http.MethodPost, c.fullURL(urlSuffix), withBody(request),
-		withBetaAssistantV1())
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -165,7 +164,7 @@ func (c *Client) DeleteAssistant(
 ) (response AssistantDeleteResponse, err error) {
 	urlSuffix := fmt.Sprintf("%s/%s", assistantsSuffix, assistantID)
 	req, err := c.newRequest(ctx, http.MethodDelete, c.fullURL(urlSuffix),
-		withBetaAssistantV1())
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -203,7 +202,7 @@ func (c *Client) ListAssistants(
 
 	urlSuffix := fmt.Sprintf("%s%s", assistantsSuffix, encodedValues)
 	req, err := c.newRequest(ctx, http.MethodGet, c.fullURL(urlSuffix),
-		withBetaAssistantV1())
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -221,7 +220,7 @@ func (c *Client) CreateAssistantFile(
 	urlSuffix := fmt.Sprintf("%s/%s%s", assistantsSuffix, assistantID, assistantsFilesSuffix)
 	req, err := c.newRequest(ctx, http.MethodPost, c.fullURL(urlSuffix),
 		withBody(request),
-		withBetaAssistantV1())
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -238,7 +237,7 @@ func (c *Client) RetrieveAssistantFile(
 ) (response AssistantFile, err error) {
 	urlSuffix := fmt.Sprintf("%s/%s%s/%s", assistantsSuffix, assistantID, assistantsFilesSuffix, fileID)
 	req, err := c.newRequest(ctx, http.MethodGet, c.fullURL(urlSuffix),
-		withBetaAssistantV1())
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -255,7 +254,7 @@ func (c *Client) DeleteAssistantFile(
 ) (err error) {
 	urlSuffix := fmt.Sprintf("%s/%s%s/%s", assistantsSuffix, assistantID, assistantsFilesSuffix, fileID)
 	req, err := c.newRequest(ctx, http.MethodDelete, c.fullURL(urlSuffix),
-		withBetaAssistantV1())
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -294,7 +293,7 @@ func (c *Client) ListAssistantFiles(
 
 	urlSuffix := fmt.Sprintf("%s/%s%s%s", assistantsSuffix, assistantID, assistantsFilesSuffix, encodedValues)
 	req, err := c.newRequest(ctx, http.MethodGet, c.fullURL(urlSuffix),
-		withBetaAssistantV1())
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
diff --git a/client.go b/client.go
index 9a1c8958..77d69322 100644
--- a/client.go
+++ b/client.go
@@ -89,9 +89,9 @@ func withContentType(contentType string) requestOption {
 	}
 }
 
-func withBetaAssistantV1() requestOption {
+func withBetaAssistantVersion(version string) requestOption {
 	return func(args *requestOptions) {
-		args.header.Set("OpenAI-Beta", "assistants=v1")
+		args.header.Set("OpenAI-Beta", fmt.Sprintf("assistants=%s", version))
 	}
 }
 
diff --git a/config.go b/config.go
index c58b71ec..599fa89c 100644
--- a/config.go
+++ b/config.go
@@ -23,6 +23,8 @@ const (
 
 const AzureAPIKeyHeader = "api-key"
 
+const defaultAssistantVersion = "v1" // This will be deprecated by the end of 2024.
+
 // ClientConfig is a configuration of a client.
 type ClientConfig struct {
 	authToken string
@@ -30,7 +32,8 @@ type ClientConfig struct {
 	BaseURL              string
 	OrgID                string
 	APIType              APIType
-	APIVersion           string                    // required when APIType is APITypeAzure or APITypeAzureAD
+	APIVersion           string // required when APIType is APITypeAzure or APITypeAzureAD
+	AssistantVersion     string
 	AzureModelMapperFunc func(model string) string // replace model to azure deployment name func
 	HTTPClient           *http.Client
 
@@ -39,10 +42,11 @@ type ClientConfig struct {
 
 func DefaultConfig(authToken string) ClientConfig {
 	return ClientConfig{
-		authToken: authToken,
-		BaseURL:   openaiAPIURLv1,
-		APIType:   APITypeOpenAI,
-		OrgID:     "",
+		authToken:        authToken,
+		BaseURL:          openaiAPIURLv1,
+		APIType:          APITypeOpenAI,
+		AssistantVersion: defaultAssistantVersion,
+		OrgID:            "",
 
 		HTTPClient: &http.Client{},
 
diff --git a/messages.go b/messages.go
index 6fd0adbc..6af11844 100644
--- a/messages.go
+++ b/messages.go
@@ -76,7 +76,8 @@ type MessageFilesList struct {
 // CreateMessage creates a new message.
 func (c *Client) CreateMessage(ctx context.Context, threadID string, request MessageRequest) (msg Message, err error) {
 	urlSuffix := fmt.Sprintf("/threads/%s/%s", threadID, messagesSuffix)
-	req, err := c.newRequest(ctx, http.MethodPost, c.fullURL(urlSuffix), withBody(request), withBetaAssistantV1())
+	req, err := c.newRequest(ctx, http.MethodPost, c.fullURL(urlSuffix), withBody(request),
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -111,7 +112,8 @@ func (c *Client) ListMessage(ctx context.Context, threadID string,
 	}
 
 	urlSuffix := fmt.Sprintf("/threads/%s/%s%s", threadID, messagesSuffix, encodedValues)
-	req, err := c.newRequest(ctx, http.MethodGet, c.fullURL(urlSuffix), withBetaAssistantV1())
+	req, err := c.newRequest(ctx, http.MethodGet, c.fullURL(urlSuffix),
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -126,7 +128,8 @@ func (c *Client) RetrieveMessage(
 	threadID, messageID string,
 ) (msg Message, err error) {
 	urlSuffix := fmt.Sprintf("/threads/%s/%s/%s", threadID, messagesSuffix, messageID)
-	req, err := c.newRequest(ctx, http.MethodGet, c.fullURL(urlSuffix), withBetaAssistantV1())
+	req, err := c.newRequest(ctx, http.MethodGet, c.fullURL(urlSuffix),
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -143,7 +146,7 @@ func (c *Client) ModifyMessage(
 ) (msg Message, err error) {
 	urlSuffix := fmt.Sprintf("/threads/%s/%s/%s", threadID, messagesSuffix, messageID)
 	req, err := c.newRequest(ctx, http.MethodPost, c.fullURL(urlSuffix),
-		withBody(map[string]any{"metadata": metadata}), withBetaAssistantV1())
+		withBody(map[string]any{"metadata": metadata}), withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -158,7 +161,8 @@ func (c *Client) RetrieveMessageFile(
 	threadID, messageID, fileID string,
 ) (file MessageFile, err error) {
 	urlSuffix := fmt.Sprintf("/threads/%s/%s/%s/files/%s", threadID, messagesSuffix, messageID, fileID)
-	req, err := c.newRequest(ctx, http.MethodGet, c.fullURL(urlSuffix), withBetaAssistantV1())
+	req, err := c.newRequest(ctx, http.MethodGet, c.fullURL(urlSuffix),
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -173,7 +177,8 @@ func (c *Client) ListMessageFiles(
 	threadID, messageID string,
 ) (files MessageFilesList, err error) {
 	urlSuffix := fmt.Sprintf("/threads/%s/%s/%s/files", threadID, messagesSuffix, messageID)
-	req, err := c.newRequest(ctx, http.MethodGet, c.fullURL(urlSuffix), withBetaAssistantV1())
+	req, err := c.newRequest(ctx, http.MethodGet, c.fullURL(urlSuffix),
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
diff --git a/run.go b/run.go
index 7c14779c..094b0a4d 100644
--- a/run.go
+++ b/run.go
@@ -226,8 +226,7 @@ func (c *Client) CreateRun(
 		http.MethodPost,
 		c.fullURL(urlSuffix),
 		withBody(request),
-		withBetaAssistantV1(),
-	)
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -247,8 +246,7 @@ func (c *Client) RetrieveRun(
 		ctx,
 		http.MethodGet,
 		c.fullURL(urlSuffix),
-		withBetaAssistantV1(),
-	)
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -270,8 +268,7 @@ func (c *Client) ModifyRun(
 		http.MethodPost,
 		c.fullURL(urlSuffix),
 		withBody(request),
-		withBetaAssistantV1(),
-	)
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -310,8 +307,7 @@ func (c *Client) ListRuns(
 		ctx,
 		http.MethodGet,
 		c.fullURL(urlSuffix),
-		withBetaAssistantV1(),
-	)
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -332,8 +328,7 @@ func (c *Client) SubmitToolOutputs(
 		http.MethodPost,
 		c.fullURL(urlSuffix),
 		withBody(request),
-		withBetaAssistantV1(),
-	)
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -352,8 +347,7 @@ func (c *Client) CancelRun(
 		ctx,
 		http.MethodPost,
 		c.fullURL(urlSuffix),
-		withBetaAssistantV1(),
-	)
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -372,8 +366,7 @@ func (c *Client) CreateThreadAndRun(
 		http.MethodPost,
 		c.fullURL(urlSuffix),
 		withBody(request),
-		withBetaAssistantV1(),
-	)
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -394,8 +387,7 @@ func (c *Client) RetrieveRunStep(
 		ctx,
 		http.MethodGet,
 		c.fullURL(urlSuffix),
-		withBetaAssistantV1(),
-	)
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -435,8 +427,7 @@ func (c *Client) ListRunSteps(
 		ctx,
 		http.MethodGet,
 		c.fullURL(urlSuffix),
-		withBetaAssistantV1(),
-	)
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
diff --git a/thread.go b/thread.go
index 291f3dca..900e3f2e 100644
--- a/thread.go
+++ b/thread.go
@@ -51,7 +51,7 @@ type ThreadDeleteResponse struct {
 // CreateThread creates a new thread.
 func (c *Client) CreateThread(ctx context.Context, request ThreadRequest) (response Thread, err error) {
 	req, err := c.newRequest(ctx, http.MethodPost, c.fullURL(threadsSuffix), withBody(request),
-		withBetaAssistantV1())
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -64,7 +64,7 @@ func (c *Client) CreateThread(ctx context.Context, request ThreadRequest) (respo
 func (c *Client) RetrieveThread(ctx context.Context, threadID string) (response Thread, err error) {
 	urlSuffix := threadsSuffix + "/" + threadID
 	req, err := c.newRequest(ctx, http.MethodGet, c.fullURL(urlSuffix),
-		withBetaAssistantV1())
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -81,7 +81,7 @@ func (c *Client) ModifyThread(
 ) (response Thread, err error) {
 	urlSuffix := threadsSuffix + "/" + threadID
 	req, err := c.newRequest(ctx, http.MethodPost, c.fullURL(urlSuffix), withBody(request),
-		withBetaAssistantV1())
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}
@@ -97,7 +97,7 @@ func (c *Client) DeleteThread(
 ) (response ThreadDeleteResponse, err error) {
 	urlSuffix := threadsSuffix + "/" + threadID
 	req, err := c.newRequest(ctx, http.MethodDelete, c.fullURL(urlSuffix),
-		withBetaAssistantV1())
+		withBetaAssistantVersion(c.config.AssistantVersion))
 	if err != nil {
 		return
 	}