Will Windows 8.1 "Expire" If Kept Offline?

I am running a fully legitimate, licensed, activated copy of Windows 8.1 x64 Pro MCE.

I've been refining a "no Windows Updates, no system networking allowed by firewall" configuration, as I'd like to keep my current perfectly working, privacy-enhanced setup running indefinitely (not moving to Win 10 yet, if ever).

By blocking Windows 8.1's attempts to communicate regularly with Microsoft's servers, am I setting myself up for it to deactivate itself in the future? I'm concerned that Microsoft may have built in a time bomb.

If the answer is yes, I can consider occasionally opening the firewall (ideally as little as possible) and allow it to do occasional license or Windows Update checks - though the chances I'll be actually installing any more of Microsoft's actual updates are slim.

As you can imagine, the information online on or around this subject is more oriented to making an unlicensed installation activated. Let's avoid discussing that if at all possible, that's not my intent.

Thanks for any knowledge on keeping Windows 8.1 running "off the grid" that you're willing to share.