diff --git a/borg/hashindex.pyx b/borg/hashindex.pyx
index 09ec89614..a27d0e8fc 100644
--- a/borg/hashindex.pyx
+++ b/borg/hashindex.pyx
@@ -4,7 +4,7 @@ import os
 cimport cython
 from libc.stdint cimport uint32_t, UINT32_MAX, uint64_t
 
-API_VERSION = 2
+API_VERSION = 3
 
 
 cdef extern from "_hashindex.c":
diff --git a/borg/helpers.py b/borg/helpers.py
index e7be78cbb..db579d34f 100644
--- a/borg/helpers.py
+++ b/borg/helpers.py
@@ -80,7 +80,7 @@ class PlaceholderError(Error):
 
 def check_extension_modules():
     from . import platform
-    if hashindex.API_VERSION != 2:
+    if hashindex.API_VERSION != 3:
         raise ExtensionModuleError
     if chunker.API_VERSION != 2:
         raise ExtensionModuleError