グローバル通知のHTMLが機能しなくなりました

[IAmGav (Gavin Perch)]

これをお読みになることをお勧めします：

No HTML in global notice

Yes, we no longer allow the global notice site setting to contain HTML, only plain text. We chose to treat it as any other user input and sanitize it. As mentioned above, the workaround would be to use a banner topic instead.