Every six months, Microsoft releases a new major Windows 10 update, but Windows doesn't install it right away. If you're not sure when you last updated, there are a few ways to check the most recent major update installation date.
How to check the installation date of the major update in Settings
First, open the “Start” menu and click on the icon to open “Settings.” You can also press Windows+i on your keyboard.
In the “Settings” window, click “System”.
In the “System” window, scroll down to the bottom of the list and select “About” in the sidebar.
On the “About” page, scroll down to the “Windows specifications” section. You’ll find the last major version of Windows installed date to the right of the “Installed on” heading
To see if you're running the latest major version of Windows 10, look at the version name, which is listed just above the "Installed on" date. Compare it to the latest version of Windows 10 and see if it matches.
If you need to share this information with someone else, Windows provides a handy way to quickly copy system (which includes the “Installed on” date) to the Clipboard. To do this, click the “Copy” button just below the “Windows specifications” list, and you can paste it later into a document, email , or message.
After that, close “Settings” and you're done.
How to check the installation date of the major update from the command line
You can also quickly check the last Windows update installation date from the Windows. First, open a prompt by clicking the “Start” menu and typing “command,” then click the “Command Prompt” icon.
When the “Command Prompt” opens, type (or copy and paste) the following command and press “Enter”:
The last major version, right after “Original Install Date” in the results that appear. When you are done, close the “Command Prompt” window.
Information source: howtogeek.com
