At one of our customers we’re migrating an old CFMX7 application to CF2021. In certain reports the Week() function is used.

<cfset oldlocale = SetLocale (“Dutch (Standard)”)>

We’re performing the initial tests in our CF2018 developer environment. In using Week() in CFMX7 the week starts at Mondays and weeknumbers are correct. Using the same source code in CF2018 the week suddenly starts at Sundays and weeknumbers are incorrect (for instance today – 21/01/2021 – returns week 4 instead of week 3).

What could be the cause for this? Or is there some kind of setting we’re missing (I checked cfadmin, but couldn’t find a lead)?