diff --git a/wagtail/utils/deprecation.py b/wagtail/utils/deprecation.py
index e7b71b8db..054706d14 100644
--- a/wagtail/utils/deprecation.py
+++ b/wagtail/utils/deprecation.py
@@ -1,9 +1,9 @@
-class RemovedInWagtail25Warning(DeprecationWarning):
+class RemovedInWagtail26Warning(DeprecationWarning):
     pass
 
 
-removed_in_next_version_warning = RemovedInWagtail25Warning
+removed_in_next_version_warning = RemovedInWagtail26Warning
 
 
-class RemovedInWagtail26Warning(PendingDeprecationWarning):
+class RemovedInWagtail27Warning(PendingDeprecationWarning):
     pass