Today I got a popup notification stating: "Your version of Windows 10 is nearing end of service. Restart and install recent version. This appears weird to me. Any advice? Scary world where you can't trust anybody any more. Thank you.

It's probably just Microsoft.
There's a new "version" of Windows 10 every so often -- I read it was every 18 months in one forum.

When is the last time you ran Windows Update?
Can you tell which version of Windows 10 it wants to install?

You may want to back up your personal files before you run the update.
Just in case -- since it would be a big update.

I suspect you have not installed the most recent updates as Jenny says. Find out what version you have by right clicking on the white Windows icon in the lower left and clicking on System. It will tell you what version you have there. You should have 1903.

I have Version 1809; 1/26/19. Newest version shows 1909. Don't they have auto updates as before? Thank you.

For updates, yes.
For a whole new version of Windows 10 they give you warning now.

I wish I could tell you for sure whether you should get version 1909.
Some people have had problems with it.

https://www.computerworld.com/article/3510463/bugs-continue-to-haunt-win10-version-1909.html

https://www.windowscentral.com/windows-10-november-2019-update-common-problems-and-how-fix-them

However apparently your version 1809 won't be getting security updates anymore, so you won't have much choice.

Just be sure to back up all your important stuff before the update.

I have had zero problems with 1903, but as Jenny said there were some problems initially. I waited until they had resolved them before I did the update. You really don't have any choice here if you want to continue using your Windows 10. As always, back up anything important. I did the update on both my tablet and my desktop and it went smoothly on both.

Thank you everybody.

Draclvr, have you updated yet from 1903 to 1909? Today, when the monthly updates came it showed that I could or should update to 1909. I did not as I am afraid to. I just let the monthly update install.

Just my modest input, I have the version 1909 since it came out in Nov of 2019 and have had zero problems with it. According to several sources this is just a small or smaller update, mostly patch fixes, according to HowtoGeek "It’s more of a service pack for Windows 10 and includes only small changes, such as a new search experience in File Explorer and the ability to create calendar events in a few clicks from the taskbar. "
If you are interested you can read the Full description from the link below:

https://www.howtogeek.com/343979/what-is-the-latest-version-of-windows-10/

1903 is the version that I have. I'm going to go ahead and install 1909 and I'll let you know how it goes. That link that Starcom provided is really good information. Seems this is a small update.

Looking at DXDIAG my version of Windows 10 says '10.0' Build 18636' am I looking in the wrong place? Todays Updates are waiting to install on a re-boot and I am not sure I want to yet.

Thank you Jenny...that reads me at 'Version 1909 OS Build 18363.657' so I have to assume I can go ahead and complete the update.

GreyFuss, the easiest way is to right click your "start" button and select System. It will tell you there.

And there it is there too...thank you Tomato Girl.

Thank you. I'll check your link Starcom and await your information Draclvr. I am just nervous about it as this will be my first time dealing with a Windows 10 version update. Well, in looking at that article and checking my computer, I see that the monthly update did not install yesterday when I thought it did?? It said it was, unless this is a second one that didn't show up separately for me. Weird!

It all says this is a small download - like in the kb range. But I'm going to wait until I leave to go bowling just in case.

So, again, I had to restart my computer for an update to install but I first checked my installed updates and the one that wanted to install showed it was already installed. I did it anyway because I didn't know what else to do. Doesn't seem to have hurt anything and only shows up as installed one time. I did, however, have 2 updates for the same thing except one is for a different build version. KB4540673 and KB4551762. Do you see any problem with this?

Did you do the update Draclvr?

Sorry, oldbroad! Yes, I did and everything is perfect. I've been running like mad today - getting my kitchen cabinets painted and it's been a week with no kitchen. They are just finishing up the painting tonight.

Thanks. Enjoy your freshed up cabinets!