diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c6ed2849f..e2b4c5e18 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -25,7 +25,7 @@ concurrency:
 
 env:
   NODE_VERSION: '24'
-  GO_VERSION: '1.24'
+  GO_VERSION: '1.25.x'
 
 jobs:
   # Detect which components have changed
diff --git a/synkronus-cli/internal/auth/auth.go b/synkronus-cli/internal/auth/auth.go
index 99487436a..0bef107f1 100644
--- a/synkronus-cli/internal/auth/auth.go
+++ b/synkronus-cli/internal/auth/auth.go
@@ -41,8 +41,21 @@ func Login(username, password string) (*TokenResponse, error) {
 		return nil, fmt.Errorf("error marshaling login data: %w", err)
 	}
 
+	// Create request with headers
+	req, err := http.NewRequest("POST", loginURL, bytes.NewBuffer(jsonData))
+	if err != nil {
+		return nil, fmt.Errorf("error creating login request: %w", err)
+	}
+	req.Header.Set("Content-Type", "application/json")
+	// Add x-formulus-version header (required by some servers)
+	apiVersion := viper.GetString("api.version")
+	if apiVersion != "" {
+		req.Header.Set("x-formulus-version", apiVersion)
+	}
+
 	// Send login request
-	resp, err := http.Post(loginURL, "application/json", bytes.NewBuffer(jsonData))
+	client := &http.Client{}
+	resp, err := client.Do(req)
 	if err != nil {
 		return nil, fmt.Errorf("login request failed for endpoint %s: %w", loginURL, err)
 	}
@@ -60,9 +73,6 @@ func Login(username, password string) (*TokenResponse, error) {
 		return nil, fmt.Errorf("error reading response body: %w", err)
 	}
 
-	// Print the raw response for debugging
-	fmt.Printf("DEBUG - Raw API response: %s\n", string(body))
-
 	// Parse response
 	var tokenResp TokenResponse
 	if err := json.Unmarshal(body, &tokenResp); err != nil {
@@ -93,8 +103,21 @@ func RefreshToken() (*TokenResponse, error) {
 		return nil, fmt.Errorf("error marshaling refresh data: %w", err)
 	}
 
+	// Create request with headers
+	req, err := http.NewRequest("POST", refreshURL, bytes.NewBuffer(jsonData))
+	if err != nil {
+		return nil, fmt.Errorf("error creating refresh request: %w", err)
+	}
+	req.Header.Set("Content-Type", "application/json")
+	// Add x-formulus-version header (required by some servers)
+	apiVersion := viper.GetString("api.version")
+	if apiVersion != "" {
+		req.Header.Set("x-formulus-version", apiVersion)
+	}
+
 	// Send refresh request
-	resp, err := http.Post(refreshURL, "application/json", bytes.NewBuffer(jsonData))
+	client := &http.Client{}
+	resp, err := client.Do(req)
 	if err != nil {
 		return nil, fmt.Errorf("refresh request failed: %w", err)
 	}
diff --git a/synkronus-cli/pkg/client/client.go b/synkronus-cli/pkg/client/client.go
index 8862ce3cd..b72b0a2ba 100644
--- a/synkronus-cli/pkg/client/client.go
+++ b/synkronus-cli/pkg/client/client.go
@@ -107,8 +107,8 @@ func (c *Client) GetVersion() (*SystemVersionInfo, error) {
 }
 
 func (c *Client) doRequest(req *http.Request) (*http.Response, error) {
-	// Add API version header
-	req.Header.Set("x-api-version", c.APIVersion)
+	// Add API version header (x-formulus-version is required by some servers)
+	req.Header.Set("x-formulus-version", c.APIVersion)
 
 	// Get authentication token
 	token, err := auth.GetToken()
@@ -447,9 +447,9 @@ func (c *Client) SyncPull(clientID string, currentVersion int64, schemaTypes []s
 
 	req.Header.Set("Content-Type", "application/json")
 
-	// Add API version header
+	// Add API version header (x-formulus-version is required by some servers)
 	if c.APIVersion != "" {
-		req.Header.Set("x-api-version", c.APIVersion)
+		req.Header.Set("x-formulus-version", c.APIVersion)
 	}
 
 	// Send request