it’s not working since Contact Form 7 version 5.8.1

We do appreciate authors have done tremendous job for this plugin. However, I don’t think it’s a good idea to improve something while creating some backward compatiable issues. As a software engineer for the past 20 years, I always think how to improve the codes without side-effect, esp this plug-in has millions of users worldwide. I strongly suggest authors re-consider any major changes next time. I have to be forced to roll back to the previous version to make my web site working. Thanks.