diff --git a/poky/meta/classes/cpan-base.bbclass b/poky/meta/classes/cpan-base.bbclass
index 9758065..93d11e1 100644
--- a/poky/meta/classes/cpan-base.bbclass
+++ b/poky/meta/classes/cpan-base.bbclass
@@ -20,7 +20,7 @@
 def cpan_upstream_check_pattern(d):
     for x in (d.getVar('SRC_URI') or '').split(' '):
         if x.startswith("https://cpan.metacpan.org"):
-            _pattern = x.split('/')[-1].replace(d.getVar('PV'), '(?P<pver>\d+.\d+)')
+            _pattern = x.split('/')[-1].replace(d.getVar('PV'), r'(?P<pver>\d+.\d+)')
             return _pattern
     return ''