Due to the competition in the software companies, they always try to develop, update and realize their software. The old versions of the software will be abandoned after one or two versions of that software are released. Microsoft makes more products; the operating systems are the first product which is hugely popular and second comes place is Office suit.
Microsoft Office was existed from decades, in 1990 the first PC version was launched and now Office 2016 was released recently in the month of September. Microsoft has abandoned old versions of Office and it is about to abandon Office 2010, because the five year lifecycle plan of Microsoft comes to an end on October 12th 2015.
If the Microsoft promotes or extends it support to 2010, even then there will be an end after 5 more years. In other words the Microsoft will not update anything in the Office 2010, like it dint updated for Office 2007, Office XP, Office 2003, Office 95 and Offive97.
Is an obsolete office still safe?
The users of the old versions of the Office will surely miss the new features available in the new versions of Microsoft Office, but the older version of Office 2000 is working perfectly. But using old version may put your PC may be at risk. The security weaknesses and bugs are available in the Office, as it is in Windows, so there are more chances of exploitation by hackers in many number of ways.
Nowadays there are many modern web browsers and anti-malware software available that can intercept many kinds of attacks, but one thing is still missing that is delivered via an infected Word document which is attached to an email. Word 2016 is made in such a way that it is trying its best to stop it in its tracks.
A serious security hole is fixed by the Microsoft in Office 2007, 2010, 2013 in August, where “An attacker who successfully exploited the vulnerabilities could run arbitrary code in the context of the current user.” That means of someone without your permission or knowledge could run a program, but that is a very bad activity.