I've always liked the fact that you can enter dates in Quickbooks easily - type 260221 and it's formatted to 26/02/2021. Not any more...
In their wisdom, Intuit seem to have decided it would be a good idea to change the entry format to DD/MM/YYYY. Miss out the / and it doesn't like it. Type YY instead of YYYY and it gives you 19YY rather than 20YY. Why? It's not helpful and, as far as I can see, it's not something they've publicised.
I'll be on to them to suggest they change it back. If you feel the same, please let them know...