Advent Ember Days for 2021 are December 15 Wednesday, 17 Friday, and 18 Saturday.
These are super-ancient special penitential days near each equinox and each solstice.
There are changes in the TLM, with particular note on the numbers of readings, graduals, tracts (with no Alleluias) and prayers:
- two readings from Isaiah then the Gospel on Wednesday
- one reading from Isaiah then the Gospel on Friday
- fully four readings from Isaiah, then from Daniel, then Daniel’s hymn!, then one from Saint Paul, then the Gospel on Saturday
Rules are said to have been fasting and abstinence on Friday (no meat, one full meal and two that don’t equal even one meal) and fasting and partial abstinence on Wednesday and Friday, the difference being meat can be included in the main meals on those days.
These penitential rules are no longer obligatory as the Canon Law promulgated in whatever epoch binds the person directly regardless of any change in the Liturgy. The present Canon Law binds those assisting at the Liturgy either of the Ancient Rite or the Novus Ordo. The present Canon Law has nothing whatsoever about Ember Days. Fasting and abstinence for the Church, for vocations, is laudatory.