MicrosoftMichael-Mertens , I may only repeat comments to another blog https://techcommunity.microsoft.com/t5/excel-blog/new-aggregation-functions-groupby-and-pivotby/bc-p/4247076/highlight/true In brief build number means practically nothing. Code could be inside your build, but functionality is not activated.
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In Excel blog deployment to production is mentioned quite seldomly, it's more announcing of new functionality for insiders. Wait for What's New for September, more chances it will be here.
Release notes also not always mentions new features, that's more about bug fixing. However, what you could see on the top of Current Channel release notes is
I assume deployment on the channel could take about the month, if nothing critical is found. Thus, if you don't have functionality now. "you'll get it eventually". Usually it goes with update on new build, but not necessary - functionality could be activated on the same build you have now without any updates.
Finally, that's my setup to confirm deployment on Current channel was started
