Microsoft is adding a Compatibility Version system to Excel. This system should prevent new features and bugfixes from breaking old spreadsheets, though it may prove to be an annoyance for Office 2024 buyers.

File compatibility is always a concern when dealing with old, regularly-updated applications like Excel. A spreadsheet that you created in Microsoft Office 2016, for example, might look like a jumbled mess when opened in the latest Excel release.

Compatibility problems are amplified in the era of always-updating, web-based software subscriptions. Microsoft 365 introduces new changes to Excel every month or so without warning, and there’s no easy way for users to roll back when something goes awry. Any change to Excel, including an updated behavior or depreciated feature, has the potential to break old spreadsheets. Bugfixes might actually be the biggest threat—you may accommodate a bug (or find a workaround for it) without even realizing that the bug exists, and when the bug is patched, your spreadsheet gets messed up.

One such bugfix, coming in 2025, addresses a text error that’s been present in Excel for several years. Microsoft is patching an issue where certain text functions, like FIND, REPLACE, LEN, MID, and SEARCH double-counted some unicode characters. These aren’t just emoji, but textual symbols and non-English alphabet characters. Spreadsheets that contained the affected unicode characters and text functions won’t be the same when the bugfix is applied.

So, Microsoft is giving us a Compatibility Version system—a hierarchy of Excel “versions” made to ease the effects of spreadsheet-breaking Excel updates. Spreadsheets made before the mid-2025 unicode bugfix will be classified as Version 1 documents, meaning that they will load without the unicode bugfix. Those made after mid-late-2025 will load under the Version 2 system, bugfixes and all.

You can manually select a workbook’s Compatibility Version by opening the “Formulas” tab, clicking the “Calculation Options” dropdown, and hovering over the “Compatibility Version” breakout menu. That said, compatibility preferences are saved directly to the spreadsheet and automatically applied when the spreadsheet is created. The average user may never need to fuss with this stuff.

However, Microsoft notes that Compatibility Versions will be both an asset and a potential pain point when collaborating with other Excel users. If a Microsoft 365 subscriber makes a Version 2 spreadsheet and sends it to someone who uses the buy-it-for-life Office 2024 suite, for example, the spreadsheet may not work properly in their version of Excel. Under this circumstance, the Microsoft 365 user should set the spreadsheet to Version 1 compatibility mode when the spreadsheet is first created.

It’s good to see file compatibility prioritized in Excel. At the same time, I suspect that Microsoft Office customers who paid $150 to avoid a monthly subscription will be frustrated when collaborating with Microsoft 365 subscribers. Compatibility Versions will roll out to Microsoft 365 subscribers in mid-late-2025, according to Microsoft.

Source: Microsoft