diff --git a/.changeset/sharp-moons-jog.md b/.changeset/sharp-moons-jog.md
new file mode 100644
index 0000000000..d3329af08e
--- /dev/null
+++ b/.changeset/sharp-moons-jog.md
@@ -0,0 +1,5 @@
+---
+'@backstage/core-plugin-api': patch
+---
+
+Deprecated the `theme` property on `AppTheme`, replacing it with `Provider`. See https://backstage.io/docs/api/deprecations#app-theme for more details.
diff --git a/.changeset/slow-moles-act.md b/.changeset/slow-moles-act.md
new file mode 100644
index 0000000000..ab920bfa5d
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+++ b/.changeset/slow-moles-act.md
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+---
+'@backstage/test-utils': patch
+---
+
+Migrated to using `createSpecializedApp`.