diff --git a/identify/extensions.py b/identify/extensions.py
index cd99e70..0443e38 100644
--- a/identify/extensions.py
+++ b/identify/extensions.py
@@ -130,6 +130,7 @@ EXTENSIONS = {
     'lr': {'text', 'lektor'},
     'lua': {'text', 'lua'},
     'm': {'text', 'objective-c'},
+    'm4': {'text', 'm4'},
     'make': {'text', 'makefile'},
     'manifest': {'text', 'manifest'},
     'map': {'text', 'map'},
diff --git a/setup.cfg b/setup.cfg
index 49fce2e..6d9ef3d 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,6 +1,6 @@
 [metadata]
 name = identify
-version = 2.5.13
+version = 2.5.15
 description = File identification library for Python
 long_description = file: README.md
 long_description_content_type = text/markdown