diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 1853d5d..f4d49e4 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -18,6 +18,7 @@ jobs:
         - { PGVER: 13 }
         - { PGVER: 14 }
         - { PGVER: 15 }
+        - { PGVER: 16 }
 
     steps:
 
diff --git a/http.c b/http.c
index 0401710..fe954a7 100644
--- a/http.c
+++ b/http.c
@@ -1161,18 +1161,18 @@ Datum http_request(PG_FUNCTION_ARGS)
 	{
 		text *content_text;
 		long content_size;
-		char *content_type;
+		char *cstr;
 		char buffer[1024];
 
 		/* Read the content type */
 		if ( nulls[REQ_CONTENT_TYPE] || ! values[REQ_CONTENT_TYPE] )
 			elog(ERROR, "http_request.content_type is NULL");
-		content_type = TextDatumGetCString(values[REQ_CONTENT_TYPE]);
+		cstr = TextDatumGetCString(values[REQ_CONTENT_TYPE]);
 
 		/* Add content type to the headers */
-		snprintf(buffer, sizeof(buffer), "Content-Type: %s", content_type);
+		snprintf(buffer, sizeof(buffer), "Content-Type: %s", cstr);
 		headers = curl_slist_append(headers, buffer);
-		pfree(content_type);
+		pfree(cstr);
 
 		/* Read the content */
 		content_text = DatumGetTextP(values[REQ_CONTENT]);