diff --git a/wchat/common/HttpClient.php b/wchat/common/HttpClient.php
index eee966d..9175a89 100644
--- a/wchat/common/HttpClient.php
+++ b/wchat/common/HttpClient.php
@@ -557,8 +557,10 @@ class HttpClient
 		}
 
 		$contentType = 'application/x-www-form-urlencoded';
-		if (isset($this->header['CONTENT-TYPE'])) {
-			$contentType = $this->header['CONTENT-TYPE'];
+		if (isset($this->header['Content-Type'])) {
+			$contentType = $this->header['Content-Type'];
+		} else if (isset($this->header['content-type'])) {
+			$contentType = $this->header['content-type'];
 		}
 
 		if (strpos($contentType, 'json') !== false) {
@@ -712,7 +714,7 @@ class HttpClient
 		if (is_array($body)) {
 			return $body;
 		}
-		$type = $data['content-type'] ?? 'text/html';
+		$type = $data['content-type'] ?? $data['Content-Type'] ?? 'text/html';
 		if (strpos($type, 'text/html') !== false) {
 			return $body;
 		} else if (strpos($type, 'json') !== false) {