Microsoft won’t deliberately prevent you from connecting to the service, but the quality of your Office 365 experience may diminish over time.
If you use older browsers and versions of Office that are not in mainstream support: OS X version 10 5 8 or later1 GB or more of RAM2 5 GB of available hard disk spaceAn Intel processorA DVD drive or connection to a local area network (if installing over a network), or an internet connection (if downloading from IUware)HFS+ hard disk format (also known as Mac OS Extended or HFS Plus)1280 x 800 or higher resolution monitorSafari 5 or later (recommended)Features of Microsoft Office 2011 for MacOffice 365 is designed to work with the latest browsers and versions of Office.