If you’re like most users, you prefer to own your software. A “perpetual” Microsoft Office license that you pay for once and own forever is far better value than a costly monthly subscription.
But which one-time-purchase version should you buy? Is Office 2021 really that different from Office 2019? And what if you’re still using Office 2016?
This guide breaks down the real differences to help you decide.
The Most Important Factor: The 2025 Security “Deadline”
Before we talk about features, you must know this: Mainstream and extended support for both Office 2016 and Office 2019 ends in October 2025.
After this date, those products will no longer receive critical security updates. Using them online will expose your PC to viruses and malware. This means that in 2025, upgrading is no longer just “nice to have”—it’s an essential security measure.
Office 2021 is supported until October 2026, giving you peace of mind.
Feature Comparison: Office 2021 vs. 2019
While Office 2019 was a minor update, Office 2021 introduced some game-changing features, especially for Excel.
| Feature | Office 2016 | Office 2019 | Office 2021 Professional Plus |
| Support Ends | Oct 2025 (Extended) | Oct 2025 (Mainstream) | Oct 2026 (Mainstream) |
| XLOOKUP | No | No | Yes |
| Dynamic Arrays | No | No | Yes |
| LET Function | No | No | Yes |
| Teams Integration | No (Skype) | No | Yes |
| Visual Refresh | Classic Ribbon | Classic Ribbon | Yes (Modern UI) |
| Full Dark Mode | No (Toolbar only) | No (Toolbar only) | Yes (True Dark Mode) |
The 3 Big Reasons to Choose Office 2021
1. You Get XLOOKUP (The VLOOKUP Killer)
For decades, VLOOKUP has been a powerful but clumsy tool in Excel. XLOOKUP (introduced in 2021) finally fixes all of its problems. It can look left, return multiple values, and is far more flexible. For anyone who spends time in Excel, this one feature is worth the entire price of the upgrade.
2. The Modern Look and True Dark Mode
Office 2021 was redesigned to match the clean, modern aesthetic of Windows 11, with softer corners and a new icon set. More importantly, it features a true dark mode that darkens the entire document background, not just the toolbars. This is a massive relief for your eyes during late-night work.
3. Real-Time Collaboration (Co-authoring)
Office 2021 integrates features previously only available in Microsoft 365. The biggest is real-time co-authoring. You can work in the same Word or Excel document with a colleague at the same time, with changes synced via OneDrive.
The Verdict: Is the Upgrade Worth It?
- If you use Office 2016 or 2019: Yes, 100%. The security deadline of October 2025 means you must upgrade to stay safe. You’ll also get a huge boost in features.
- If you are buying new: Office 2021 Professional Plus is the clear winner. It’s the most modern, feature-rich perpetual license you can buy and has the longest support life.
Don’t wait until your software is vulnerable. At WindowsKeyShop.com, you can get a lifetime license for Microsoft Office 2021 Professional Plus at a fraction of the cost of a subscription.
Upgrade today. Shop our genuine Office 2021 keys here.
Yes, upgrading from Office 2016 or 2019 is highly recommended in 2025