diff --git a/CMakeLists.txt b/CMakeLists.txt
index 813f632f7..5a5dccac1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -4,8 +4,11 @@ project(cmark
   LANGUAGES C CXX
   VERSION 0.31.2)
 
-set(CMAKE_C_STANDARD 99)
-set(CMAKE_C_STANDARD_REQUIRED YES)
+if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.21)
+  set(CMAKE_C_STANDARD 23)
+else()
+  set(CMAKE_C_STANDARD 11)
+endif()
 set(CMAKE_C_EXTENSIONS NO)
 
 if(CMAKE_BUILD_TYPE STREQUAL Asan)
diff --git a/src/utf8.c b/src/utf8.c
index 48697c77d..be252e7e1 100644
--- a/src/utf8.c
+++ b/src/utf8.c
@@ -242,9 +242,9 @@ void cmark_utf8proc_case_fold(cmark_strbuf *dest, const uint8_t *str,
         cmark_strbuf_put(dest, str, char_len);
     } else if (char_len >= 0) {
       uint32_t key = c;
-      uint32_t *entry = bsearch(&key, cf_table,
-                                CF_TABLE_SIZE, sizeof(uint32_t),
-                                cf_compare);
+      const uint32_t *entry = bsearch(&key, cf_table,
+                                      CF_TABLE_SIZE, sizeof(uint32_t),
+                                      cf_compare);
       if (entry == NULL) {
         cmark_strbuf_put(dest, str, char_len);
       } else {