diff --git a/flopy/utils/util_list.py b/flopy/utils/util_list.py
index d79c653b35..c9ece34108 100644
--- a/flopy/utils/util_list.py
+++ b/flopy/utils/util_list.py
@@ -695,7 +695,7 @@ def write_transient(self, f, single_per=None, forceInternal=False):
 
             if kper_vtype == np.recarray:
                 name = f.name
-                if self.__binary:
+                if self.__binary or not numpy114:
                     f.close()
                     # switch file append mode to binary
                     with open(name, 'ab+') as f: