diff --git a/scripts/update_api.py b/scripts/update_api.py
index 03aa80638..f5d935514 100755
--- a/scripts/update_api.py
+++ b/scripts/update_api.py
@@ -689,7 +689,7 @@ def mk_java(java_src, java_dir, package_name):
     java_native.write('}\n')
     java_wrapper = open(java_wrapperf, 'w')
     pkg_str = package_name.replace('.', '_')
-    with open(f"{java_src}/NativeStatic.txt") as ins:
+    with open(java_src + "/NativeStatic.txt") as ins:
         for line in ins:
             java_wrapper.write(line)            
     for name, result, params in _dotnet_decls: