No support is thus included for Windows 7 or even Windows 8.1 which is only four years old at this moment. You'll obviously still have the older version of Office to use or you can upgrade to Office 365 which offers online tools.
The preliminary version of Office 2019 will become available somewhere around summer but at this point we don't have an official, final release date. Microsoft will keep developing the tools until they're passing the company's quality checks after which they will release the final version of Office 2019.
Office for Mac is considered within Microsoft a different product and thus this restriction is not applied to products on Apple computers.