We are still dealing with the issue of old outdated websites using old version of joomla, wordpress and drupal. I still dont know where people get the idea that a website lasts forever. The environment that makes a website work is constantly changing. Hosting companies update their servers to use the latest version of PHP and MySQL, thus rendering these older sites broken. The websites and the host services and no longer communicate. The sites just cant run. The frustration for the hosting companies is they know they will crash these old sites, bit they have to upgrade, if for no other reasons, server security and improved functionality.
For security, the old sites are so dangerously insecure, and hackable, that the hosting compnaies suspend the sites because a hacker can actually go right through a website to the server level, then travel horizontally and take out all the other sites on a shared server. The host has to protect everyone.
Sometimes the site ownsers call the host and the host says that they have no issues and the old site will be fine. But then there is virus scanning software. If your site visitors have scanners integrated into thier browers, these scanners can block the website from your user. They are set to detect old versions of CMS systems as security risks. So even though your host may not have suspended your site as of yet, your customers may not be able to access due to their own scanner programs.
I have personally seen 38 websites get suspended recently. Once suspended your developer may not even be allowed in to retrieve the files. Sometimes I can, and sometimes I cant. Its really horrible.
The only solution is to upgrade. In most cases its not that big a deal. Its only if your site has been customized and/or the 3rd party extensions you used are not available that it becomes complicated.
Don't wait, we can work something out to get your website upgraded. Don't take the chance of having your website down during the peak of the holidays.