diff --git a/ifc/src/lib.rs b/ifc/src/lib.rs
index 450b889..5ede0c0 100644
--- a/ifc/src/lib.rs
+++ b/ifc/src/lib.rs
@@ -250,8 +250,12 @@ impl From<chrono::NaiveDate> for IFC {
             {
                 days = days - 1;
             }
-            let month: u8 = (days / 28).try_into().unwrap();
-            let day: u8 = (days % 28).try_into().unwrap();
+            let mut month: u8 = (days / 28).try_into().unwrap();
+            let mut day: u8 = (days % 28).try_into().unwrap();
+            if day == 0 {
+                month = month - 1;
+                day = 28;
+            }
             Self::Day(Day {
                 year: date.year(),
                 month: month + 1,
@@ -268,167 +272,6 @@ impl From<IFC> for chrono::NaiveDate {
     }
 }
 
-/*
-impl IFC {
-    pub fn year_day(year: u32) -> Self {
-        Self {
-            year,
-            ordinal: if is_leap_year(year) { 366 } else { 365 }
-        }
-    }
-
-}
-*/
-
-/*
-impl From<chrono::Date<chrono::Utc>> for IFC {
-    fn from(d: chrono::Date<chrono::Utc>) -> IFC {
-        IFC::from(d.naive_utc())
-    }
-}
-
-impl From<chrono::Date<chrono_tz::Tz>> for IFC {
-    fn from(d: chrono::Date<chrono_tz::Tz>) -> IFC {
-        IFC::from(d.naive_utc())
-    }
-}
-
-impl From<chrono::NaiveDate> for IFC {
-    fn from(d: NaiveDate) -> IFC {
-        //println!("d: {} [{}]", d.format("%Y-%m-%d"), d.ordinal());
-        IFC {
-            year: (d.year() + 10000) as u32,
-            ordinal: d.ordinal0(),
-            leap_year: is_leap_year(d.year()),
-        }
-    }
-}
-*/
-
-/*
-impl Datelike for IFC {
-    fn year(&self) -> i32 {
-        // self.year as i32
-        unimplemented!()
-    }
-    fn month(&self) -> u32 {
-        // self.month0() + 1
-        unimplemented!()
-    }
-    fn month0(&self) -> u32 {
-        /*
-        if self.leap_year && self.ordinal == 365 {
-            12
-        } else if self.leap_year && self.ordinal == 168 {
-            5
-        } else {
-            self.ordinal / 28
-        }
-        */
-        unimplemented!()
-    }
-    fn day(&self) -> u32 {
-        // self.day0() + 1
-        unimplemented!()
-    }
-    fn day0(&self) -> u32 {
-        /*
-        if self.leap_year {
-            if self.ordinal == 365 {
-                28
-            } else if self.ordinal == 168 {
-                28
-            } else if self.ordinal > 168 {
-                (self.ordinal - 1).rem_euclid(28) as u32
-            } else {
-                self.ordinal.rem_euclid(28) as u32
-            }
-        } else {
-            if self.ordinal == 364 {
-                28
-            } else {
-                self.ordinal.rem_euclid(28) as u32
-            }
-        }
-        */
-        unimplemented!()
-    }
-    fn ordinal(&self) -> u32 {
-        // self.ordinal + 1
-        unimplemented!()
-    }
-    fn ordinal0(&self) -> u32 {
-        // self.ordinal
-        unimplemented!()
-    }
-    fn weekday(&self) -> chrono::Weekday {
-        if self.day0() == 28 {
-            chrono::Weekday::Sat
-        } else {
-            match self.day0().rem_euclid(7) {
-                0 => chrono::Weekday::Sun,
-                1 => chrono::Weekday::Mon,
-                2 => chrono::Weekday::Tue,
-                3 => chrono::Weekday::Wed,
-                4 => chrono::Weekday::Thu,
-                5 => chrono::Weekday::Fri,
-                6 => chrono::Weekday::Sat,
-                _ => panic!("rem_euclid should not return anything outside the 0..6 range"),
-            }
-        }
-    }
-    fn iso_week(&self) -> chrono::IsoWeek {
-        panic!("iso_week is not implemented because chrono does not expose any constructors for IsoWeek!");
-    }
-    fn with_year(&self, year: i32) -> Option<IFC> {
-        /*
-        Some(IFC {
-            year: (year as u32) + 10000,
-            ordinal: self.ordinal,
-            leap_year: is_leap_year(year),
-        })
-        */
-        unimplemented!()
-    }
-    fn with_month(&self, month: u32) -> Option<IFC> {
-        // Some(IFC::ymd(self.year, month as u8, self.day() as u8))
-        unimplemented!()
-    }
-    fn with_month0(&self, month: u32) -> Option<IFC> {
-        // Some(IFC::ymd(self.year, month as u8 + 1, self.day() as u8))
-        unimplemented!()
-    }
-    fn with_day(&self, day: u32) -> Option<IFC> {
-        // Some(IFC::ymd(self.year, self.month() as u8, day as u8))
-        unimplemented!()
-    }
-    fn with_day0(&self, day: u32) -> Option<IFC> {
-        // Some(IFC::ymd(self.year, self.month() as u8, day as u8 + 1))
-        unimplemented!()
-    }
-    fn with_ordinal(&self, ordinal: u32) -> Option<IFC> {
-        /*
-        Some(IFC {
-            year: self.year,
-            ordinal,
-            leap_year: self.leap_year,
-        })
-        */
-        unimplemented!()
-    }
-    fn with_ordinal0(&self, ordinal: u32) -> Option<IFC> {
-        /*
-        Some(IFC {
-            year: self.year,
-            ordinal: ordinal + 1,
-            leap_year: self.leap_year,
-        })
-        */
-        unimplemented!()
-    }
-}
-*/
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -612,10 +455,34 @@ mod tests {
             IFC::from(NaiveDate::from_ymd_opt(12022, 1, 1).unwrap()),
             IFC::ymd(12022, 1, 1).unwrap()
         );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12022, 1, 2).unwrap()),
+            IFC::ymd(12022, 1, 2).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12022, 1, 3).unwrap()),
+            IFC::ymd(12022, 1, 3).unwrap()
+        );
+        assert_eq!(
+            IFC::from(chrono::NaiveDate::from_ymd_opt(2023, 01, 26).unwrap()),
+            IFC::ymd(2023, 1, 26).unwrap()
+        );
+        assert_eq!(
+            IFC::from(chrono::NaiveDate::from_ymd_opt(2023, 01, 27).unwrap()),
+            IFC::ymd(2023, 1, 27).unwrap()
+        );
+        assert_eq!(
+            IFC::from(chrono::NaiveDate::from_ymd_opt(2023, 01, 28).unwrap()),
+            IFC::ymd(2023, 1, 28).unwrap()
+        );
         assert_eq!(
             IFC::from(NaiveDate::from_ymd_opt(12022, 1, 29).unwrap()),
             IFC::ymd(12022, 2, 1).unwrap()
         );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12022, 1, 30).unwrap()),
+            IFC::ymd(12022, 2, 2).unwrap()
+        );
         assert_eq!(
             IFC::from(NaiveDate::from_ymd_opt(12022, 2, 26).unwrap()),
             IFC::ymd(12022, 3, 1).unwrap()
@@ -644,6 +511,10 @@ mod tests {
             IFC::from(NaiveDate::from_ymd_opt(12022, 8, 13).unwrap()),
             IFC::ymd(12022, 9, 1).unwrap()
         );
+        assert_eq!(
+            IFC::from(chrono::NaiveDate::from_ymd_opt(2023, 08, 12).unwrap()),
+            IFC::ymd(2023, 8, 28).unwrap()
+        );
         assert_eq!(
             IFC::from(NaiveDate::from_ymd_opt(12022, 9, 10).unwrap()),
             IFC::ymd(12022, 10, 1).unwrap()