Overview
- One UI 8.5 and Samsung phones updated with the March 2026 security patch now reject fonts added by third‑party apps such as zFont 3.
- Users report they cannot switch to those fonts anymore and see a prompt that says “This font is not supported” with options to delete or cancel.
- The developer of zFont 3 confirmed on Reddit that the app no longer works on non‑root devices running the new software.
- Samsung’s March security notes cite a fix for improper verification of cryptographic signatures in Font Settings, which adds proper checks that stop unverified fonts from loading.
- Official Galaxy Store fonts still work because they pass Samsung’s validation, leaving affected users to remove incompatible fonts or use approved options unless they root their phones.