The only truly locked date is that you can't post to a closed GL period.  Otherwise the Sage features for date control are primarily warnings.

The "Accounting Date" is just the module date (what you see in the bottom tool-bar, which is used as the default date during data entry), and does nothing to control a user typing in a far future date for invoices / receipts / adjustments...

With v2019 Sage added a new "Use Document Date Warning" feature to help with that, and while it is still just a warning which could be ignored, it does help unintentionally posting to the wrong year.

thanks..the think I don't get is that it's only in January that we have this issue. The rest of the year, we are unable to post to such a far out future date

I'm pretty sure you would be able... it's just that users who type dates as month and day only, entering December dates in January doesn't work as expected.  The year auto-fills in to the current year, so "1231" is interpreted automatically as 12/31/2021.

you might be correct about that, if not, i'll let you know in February! thanks again