Today Microsoft Exchange 2007 reached the end of life. That means Microsoft will no longer provide:
- Technical support for problems that may occur
- Bug fixes for issues that are discovered and that may impact the stability and usability of the server
- Security fixes for vulnerabilities that are discovered and that may make the server vulnerable to security breaches
- Time zone updates
That means its time to consider an upgrade to Exchange Online (via Office 365) or Exchange 2016.