diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index f5881ae..10b0f4d 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -11,7 +11,7 @@ repos:
     -   id: requirements-txt-fixer
     -   id: trailing-whitespace
 -   repo: https://github.com/asottile/setup-cfg-fmt
-    rev: v1.18.0
+    rev: v1.19.0
     hooks:
     -   id: setup-cfg-fmt
 -   repo: https://github.com/PyCQA/flake8
diff --git a/identify/extensions.py b/identify/extensions.py
index 17f86a7..412fb3c 100644
--- a/identify/extensions.py
+++ b/identify/extensions.py
@@ -154,6 +154,7 @@ EXTENSIONS = {
     'r': {'text', 'r'},
     'rake': {'text', 'ruby'},
     'rb': {'text', 'ruby'},
+    'rng': {'text', 'xml', 'relax-ng'},
     'rs': {'text', 'rust'},
     'rst': {'text', 'rst'},
     's': {'text', 'asm'},
diff --git a/setup.cfg b/setup.cfg
index dfd0811..5fe1d27 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,6 +1,6 @@
 [metadata]
 name = identify
-version = 2.3.3
+version = 2.3.4
 description = File identification library for Python
 long_description = file: README.md
 long_description_content_type = text/markdown