Apple Event: May 7th at 7 am PT
I found that the first time of this question raising was in 2021. So why this mistake or bug had not been fixed till now. I just try to open a numbers file which I opened everyday on my Macbook, but it shows "To open this spreadsheet, you'll need the latest version of numbers".
BTW, it really give a lot go negative affect on my work.
MacBook Pro
My Macbook is running Mojave. The Numbers app is now in the latest version which this Mac could get. I solve this problem through iCloud.com. I found an earlier version of this file from iCloud.com. Then, I can open it off-line.
So it looks as if this is not about a "mistake" or a "bug" but instead a case of outdated hardware and software.
Glad to hear you could retrieve a version of the document that still works.
SG
Have you gone to the Mac App Store and upgraded Numbers to the latest version? (currently v. 12.1)
SG
Can not open the file with .numbers
