I’ve had a few people ask me if they can use their old versions of Outlook on Windows 10 or 11.

I'm a realist. I know some consumers (and some businesses) can't afford to upgrade with every new Office version and want to make their purchase last as long as possible. But there comes a time when you need to say "Enough. Time to bite the bullet and upgrade."

The short version: Yes, older versions of Outlook will work on Windows 11. Some features might not work well (like Instant Search) but it should send and receive mail and handle calendar and contacts ok. You may not be able to use it to connect to an Exchange server, but it should work fine with POP and IMAP accounts.

Search Solution: remove Outlook from Windows Search or set a registry key to use the old, slower built-in search function.

Office 2021 is now available, but don’t get “new version envy” if you have Office 2016, 2019 or 365. If you have Office 365, you have the newest version of Office.  Office 2021 is newer than Office 2016 and 2019, but many users won’t get much benefit in upgrading (besides a lighter wallet), especially if they don’t use an Exchange mailbox. Most of the new features are targeted to business users, not POP and IMAP. Office 2021 is Office 16.0, same as Office 2016, 2019 and 365. Addins, registry hacks and file paths are identical between the four versions. Many features are identical.

If there are new features it has that you’d like, consider a subscription to Office 365 instead. If you are a frequent upgrader and need the latest and greatest, or have more than one computer, it can be less expensive overall.

But... just because you can do something, should you?

Using older versions of Outlook, including Outlook 2007 and Outlook 2003, is not recommended. The older versions are less secure and do not support modern authentication or encryption methods. Outlook 2007 is 15 years old, and Outlook 2003 is 20 years old - it's time to retire them. Even Outlook 2010 is getting "long in the tooth" and needs to be considered for retirement.

Should you run out and upgrade to Office 365 or Office 2021? Well, you could... but my policy is new computer, newest Office version. I know there are a lot of people still using older versions of Office, but if you are purchasing a new computer, you should upgrade to a current version of Office.

The Office Home and Student version is the least expensive of the retail (perpetual) versions but does not include Outlook, only Word, Excel, and PowerPoint. It is licensed only for home or personal use.

If you have an older computer and won't be replacing it in the near future, I don't usually recommend upgrading to the current version of Office, in part because the newer versions may not work on your Windows OS. For most people, especially home users, having the latest software is not important, especially if you use POP or IMAP and have an older computer. You won't benefit from many of the new and improved features.

However, if you have a newer computer with Windows 10, are upgrading it to Windows 11 and have an older version of Office, upgrade your Office to the latest version too.

I'm a huge fan of Microsoft Office 365 subscriptions. With it, you always have the latest version of Office (newer than Office 2021!) and can install it on multiple computers you use.

You can share the Office Family plan with up to five additional family members. And each user gets 1TB of OneDrive storage space and a 50GB Outlook.com mailbox. This compares to the single purchase, which is good for one computer, will not get features updates, and does not get additional OneDrive storage space.

Note: The Family subscription is licensed for consumer use only, not for business use.

You can redeem Office 365 Family or Personal key codes in your account before your expiration date and can "bank" up to five years on your subscription. If you purchase or receive a code to redeem, no need to wait for your expiration date (and risk forgetting where you put the card.)

Office 365 Mailboxes

If you have an Office 365 mailbox, you may have issues connecting older versions of Outlook to the Office 365 Exchange server, but this is due to changes in Exchange and not to your desktop.

Starting November 1, 2021 the older versions of Outlook for Windows, as part of Office and Microsoft 365 Apps, will not be able to connect with Office 365 and Microsoft 365 services. This change is rolling out over several months and is expected to be completed by the spring of 2022.

If Outlook is a newer version than listed above but not a supported version, users may experience connectivity issues, which may include issues synchronizing and sharing calendars.

Not surprisingly, Microsoft recommends users upgrade to the supported versions of Office and Microsoft 365 Apps.