@sdetweil said in Builtin calendar module: dateformat, timeformat: @DomRep unfortunately the dateFormat/timeFormat/showEnd options apply to ALL calendars, so they would have to be above the calendars:[] list in the doc, the first section of parameters are for ALL calendars… the second section is for individual calendars… So there’s my misunderstanding: It’s a global setting :) Actually, having to set these config values for all calendars alike is fine for me… I just started to test the effect for “calendar two” because I wanted to compare the effect against the others two. In my original post I emphasized this (the SECOND calendar) just to make following my pursuit easier for forum readers. Thank you @sdetweil for the clarification :)