diff --git a/html/changelogs/AutoChangeLog-pr-12217.yml b/html/changelogs/AutoChangeLog-pr-12217.yml
new file mode 100644
index 0000000000..2be7aad431
--- /dev/null
+++ b/html/changelogs/AutoChangeLog-pr-12217.yml
@@ -0,0 +1,4 @@
+author: "Putnam3145"
+delete-after: True
+changes: 
+  - refactor: "Gas mixtures now live entirely in a DLL."