before about the French Republican Calendar iPhone app called Calendrier. It seems that it has been updated. Originally it used a calculation that skipped a leap year every 128 years, so that all Republican years between 128 and 256 (1919 and 2047 CE) start on September 23. Version 1.2, released 2010 March 4 (MJD 55259/14 Ventôse an CCXVIII) has all years starting on the autumnal equinox in Paris, as during the French Revolution, with an option to display the current date according to Romme's Gregorian-style proposal to skip leap days on most century years. (Romme went to the guillotine before it could be adopted.) Under Romme's plan, all years between 200 and 300 (1991 and 2091 CE) start on September 22. Under the original rule, all years between 141 and 300 (1932 and 2091 CE) start on either September 22 or 23.
The app also now converts Gregorian dates between 1792 and 2195 CE (1 and 404 ER) to Republican dates, although apparently only by the equinoctial rule. (Not sure why the Gregorian months appear to be in Spanish.) Now I'm actually tempted to pay $1.99 for it!
Primidi 21 Ventôse an CCXVIII à 3hd 86md t.m.P.