diff --git a/src/borg/algorithms/checksums.pyx b/src/borg/algorithms/checksums.pyx
index 6645dd0fe..75c67280b 100644
--- a/src/borg/algorithms/checksums.pyx
+++ b/src/borg/algorithms/checksums.pyx
@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 from ..helpers import bin_to_hex
 
 from libc.stdint cimport uint32_t
diff --git a/src/borg/chunker.pyx b/src/borg/chunker.pyx
index d2b44f686..9addb051a 100644
--- a/src/borg/chunker.pyx
+++ b/src/borg/chunker.pyx
@@ -1,4 +1,4 @@
-# -*- coding: utf-8 -*-
+# cython: language_level=3
 
 API_VERSION = '1.1_01'
 
diff --git a/src/borg/compress.pyx b/src/borg/compress.pyx
index 8fd3323ea..f1e4fd331 100644
--- a/src/borg/compress.pyx
+++ b/src/borg/compress.pyx
@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 """
 borg.compress
 =============
diff --git a/src/borg/crypto/low_level.pyx b/src/borg/crypto/low_level.pyx
index db0ea8af6..21c41f7f2 100644
--- a/src/borg/crypto/low_level.pyx
+++ b/src/borg/crypto/low_level.pyx
@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 """A thin OpenSSL wrapper"""
 
 import hashlib
diff --git a/src/borg/hashindex.pyx b/src/borg/hashindex.pyx
index f14eeea92..57d13240d 100644
--- a/src/borg/hashindex.pyx
+++ b/src/borg/hashindex.pyx
@@ -1,4 +1,5 @@
-# -*- coding: utf-8 -*-
+# cython: language_level=3
+
 from collections import namedtuple
 import locale
 import os
diff --git a/src/borg/item.pyx b/src/borg/item.pyx
index 7c698baf7..1dc0b1f61 100644
--- a/src/borg/item.pyx
+++ b/src/borg/item.pyx
@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 import stat
 from collections import namedtuple
 
diff --git a/src/borg/platform/darwin.pyx b/src/borg/platform/darwin.pyx
index 080d8a69d..f8bdd17a5 100644
--- a/src/borg/platform/darwin.pyx
+++ b/src/borg/platform/darwin.pyx
@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 import os
 
 from ..helpers import user2uid, group2gid
diff --git a/src/borg/platform/freebsd.pyx b/src/borg/platform/freebsd.pyx
index cc6d00bd1..2797da309 100644
--- a/src/borg/platform/freebsd.pyx
+++ b/src/borg/platform/freebsd.pyx
@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 import os
 
 from ..helpers import posix_acl_use_stored_uid_gid
diff --git a/src/borg/platform/linux.pyx b/src/borg/platform/linux.pyx
index dc980d7c5..d800bdfb1 100644
--- a/src/borg/platform/linux.pyx
+++ b/src/borg/platform/linux.pyx
@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 import os
 import re
 import stat
diff --git a/src/borg/platform/posix.pyx b/src/borg/platform/posix.pyx
index 0701ab9e8..6b15ce3b3 100644
--- a/src/borg/platform/posix.pyx
+++ b/src/borg/platform/posix.pyx
@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 import errno
 import os