A year from today, Microsoft will issue the final public security update for Windows 7, ending the operating system's 10-year run.
Here are some of the important numbers related to Windows 7's final 12 months.
The label for the version of Windows slated to replace Windows 7 as the default OS in the enterprise. Currently, Windows 10's adoption rate lags behind Windows 7's at the same point in its post-launch timeline. In March 2013, 41 months after its debut, Windows 7 powered approximately 49 per cent of all Windows PCs.
The number of Patch Tuesday security releases remaining for Windows 7. These updates, issued on the second Tuesday of each month, are the primary patch collections for newly reported or discovered vulnerabilities.
The number of months Microsoft will support the final Windows 10 feature upgrade available prior to Windows 7's retirement. The feature upgrade, likely carrying the labels "Windows 10 October 2019 Update" and "1909," will probably begin reaching users in October.
Last year, Microsoft extended support for individual feature upgrades from 18 to 30 months when those upgrades were issued in the fall for the Enterprise and Education editions only. Windows 10's spring feature upgrades continue to receive only 18 months of security and non-security updates.
The percentage of all Windows PCs that will run Windows 7 at its retirement, based on a rolling 12-month average of change tracked by Net Applications; that average was then projected into the future. The number has fluctuated significantly over the last two years, from a low of 29 per cent to nearly 40 per cent.
It's also the maximum number of months Microsoft will offer corporate customers "Windows 7 Extended Security Updates" (ESU) after the January 2020 support retirement.
The extended support will be available only for PCs running Windows 7 Professional or Windows 7 Enterprise, and then only if those operating systems were obtained via a volume licensing deal.
Microsoft will discount ESU for customers who also have Software Assurance plans in place for Windows or have subscriptions to Windows 10 Enterprise or Windows 10 Education, including the Microsoft 365 subscription.
Windows 7 ESU will be sold in 12-month increments, with as many as two extensions of the additional-support plan. Unlike the per-user licensing model Microsoft has taken to for Windows 10, ESU will be sold on a per-device basis.
The percentage of all Windows personal computers currently running Windows 7, according to U.S. analytics company Net Applications. Windows 7 slipped to second place on the Windows list - finally bested by the newer Windows 10 - only last month.
The percentage of all Windows PCs that ran Windows 7 at the operating system's peak, which was in June 2015, the month before the launch of Windows 10.
Amount, in dollars, of a single license to Windows 10 Pro for upgrading a compatible Windows 7 personal computer. An upgrade from Windows 7 to the less expensive, but also less capable, Windows 10 Home costs $140.
Additional amount, in dollars, that Microsoft claimed it cost enterprises to continue to run Windows 7 for three years, compared to the costs of Windows 10.
The assertion was made in April 2017, when Windows 7 had less than three years of remaining support. Microsoft's claim was based on analysis done by Forrester Research but paid for by the Redmond, Wash. developer of Windows.
The approximate number of personal computers worldwide that currently rely on Windows 7. This number was calculated by multiplying the current Windows 7 share of all Windows personal computers by 1.5 billion, the number Microsoft regularly cites as the global Windows installed base.
In comparison, Windows 8 and Windows 8.1 account for about 93 million PCs, and Windows 10 powers around 682 million machines.