diff --git a/ext/mysql2/client.c b/ext/mysql2/client.c
index 4f62e463..fbc73572 100644
--- a/ext/mysql2/client.c
+++ b/ext/mysql2/client.c
@@ -121,8 +121,8 @@ struct nogvl_select_db_args {
 static VALUE rb_set_ssl_mode_option(VALUE self, VALUE setting) {
   unsigned long version = mysql_get_client_version();
 
-  if (version < 50703) {
-    rb_warn( "Your mysql client library does not support setting ssl_mode; full support comes with 5.7.11." );
+  if (version < 50630 || (version >= 50700 && version < 50703)) {
+    rb_warn( "Your mysql client library does not support setting ssl_mode; full support comes with 5.6.36+, 5.7.11+, 8.0+" );
     return Qnil;
   }
 #if defined(HAVE_CONST_MYSQL_OPT_SSL_VERIFY_SERVER_CERT) || defined(HAVE_CONST_MYSQL_OPT_SSL_ENFORCE)
@@ -1723,7 +1723,7 @@ void init_mysql2_client() {
   rb_const_set(cMysql2Client, rb_intern("SESSION_TRACK_TRANSACTION_STATE"), INT2NUM(SESSION_TRACK_TRANSACTION_STATE));
 #endif
 
-#if defined(FULL_SSL_MODE_SUPPORT) // MySQL 5.7.11 and above
+#if defined(FULL_SSL_MODE_SUPPORT) // MySQL 5.6.36 and MySQL 5.7.11 and above
   rb_const_set(cMysql2Client, rb_intern("SSL_MODE_DISABLED"), INT2NUM(SSL_MODE_DISABLED));
   rb_const_set(cMysql2Client, rb_intern("SSL_MODE_PREFERRED"), INT2NUM(SSL_MODE_PREFERRED));
   rb_const_set(cMysql2Client, rb_intern("SSL_MODE_REQUIRED"), INT2NUM(SSL_MODE_REQUIRED));
diff --git a/ext/mysql2/result.c b/ext/mysql2/result.c
index 5cacd5ac..23ec611e 100644
--- a/ext/mysql2/result.c
+++ b/ext/mysql2/result.c
@@ -143,6 +143,7 @@ static size_t rb_mysql_result_memsize(const void * wrapper) {
   return memsize;
 }
 
+#ifdef HAVE_RB_GC_MARK_MOVABLE
 static void rb_mysql_result_compact(void * wrapper) {
   mysql2_result_wrapper * w = wrapper;
   if (w) {
@@ -153,6 +154,7 @@ static void rb_mysql_result_compact(void * wrapper) {
     rb_mysql2_gc_location(w->statement);
   }
 }
+#endif
 
 static const rb_data_type_t rb_mysql_result_type = {
   "rb_mysql_result",
diff --git a/ext/mysql2/statement.c b/ext/mysql2/statement.c
index 2af1c486..5506526e 100644
--- a/ext/mysql2/statement.c
+++ b/ext/mysql2/statement.c
@@ -33,12 +33,14 @@ static size_t rb_mysql_stmt_memsize(const void * ptr) {
   return sizeof(*stmt_wrapper);
 }
 
+#ifdef HAVE_RB_GC_MARK_MOVABLE
 static void rb_mysql_stmt_compact(void * ptr) {
   mysql_stmt_wrapper *stmt_wrapper = ptr;
   if (!stmt_wrapper) return;
 
   rb_mysql2_gc_location(stmt_wrapper->client);
 }
+#endif
 
 static const rb_data_type_t rb_mysql_statement_type = {
   "rb_mysql_statement",