Microsoft FrontPage is a web publishing software that has existed for over 18 years. However official mainstream support was dropped for the product by Microsoft on 4/14/2009, and extended support ended on 4/8/2014. FrontPage Server Extensions are a software technology that allows FrontPage clients to communicate with web servers, and provide additional functionality intended for websites.
From the Microsoft:
FrontPage Server Extensions are considered deprecated technology and are being phased out of Microsoft products in favor of modern standards. Designers who use FrontPage Server Extensions components are likely to encounter problems with modern Web browsers. Many hosting companies are also dropping support for FrontPage Server Extensions due to the fact that Microsoft hasn’t released a new version in many years.
Frequent security problems have marred the history of this Microsoft proprietary technology and ExactHosting has disabled FrontPage Server Extensions, to protect our servers from the many vulnerabilities.
Any FrontPage user that wants to update their site, will no longer be able to publish with or utilize the features that FrontPage extensions allows for. You may decide to continue using FrontPage, however please note that as web standards, and browsers evolve, FrontPage sites may not work as expected.