We've been running F# in production since 2014 - almost 7 years. It is quite shocking to hear anyone imply that F# is not ready for production use - that it is just "cool" tech. (when has F# ever been cool in the minds of the masses?)

I suspect you'll say "7 years is nothing" and maybe it is nothing. But it is still something. It is long enough that we made a couple bad framework/library dependency choices early on and to have learnt lessons from such mistakes.

By far the biggest technical challenge we've faced in that time is the .NET 5 migration - but even that might turn out to be a lot easier than I currently envisage.