diff --git a/date.h b/date.h
index 6761b6d..80766bb 100644
--- a/date.h
+++ b/date.h
@@ -101,9 +101,6 @@ template <class Duration>
 using local_seconds = local_time<std::chrono::seconds>;
 using local_days    = local_time<days>;
 
-// deprecated:
-using day_point = sys_days;
-
 // types
 
 struct last_spec
@@ -1326,19 +1323,14 @@ year::is_leap() const NOEXCEPT
 }
 
 CONSTCD11 inline year::operator int() const NOEXCEPT {return y_;}
-CONSTCD11 inline bool year::ok() const NOEXCEPT {return min() <= *this && *this <= max();}
+CONSTCD11 inline bool year::ok() const NOEXCEPT {return true;}
 
 CONSTCD11
 inline
 year
 year::min() NOEXCEPT
 {
-    using namespace std::chrono;
-    static_assert(sizeof(seconds)*CHAR_BIT >= 41, "seconds may overflow");
-    static_assert(sizeof(hours)*CHAR_BIT >= 30, "hours may overflow");
-    return sizeof(minutes)*CHAR_BIT < 34 ?
-        year{1970} + duration_cast<years>(minutes::min()) :
-        year{std::numeric_limits<short>::min()};
+    return year{std::numeric_limits<short>::min()};
 }
 
 CONSTCD11
@@ -1346,12 +1338,7 @@ inline
 year
 year::max() NOEXCEPT
 {
-    using namespace std::chrono;
-    static_assert(sizeof(seconds)*CHAR_BIT >= 41, "seconds may overflow");
-    static_assert(sizeof(hours)*CHAR_BIT >= 30, "hours may overflow");
-    return sizeof(minutes)*CHAR_BIT < 34 ?
-        year{1969} + duration_cast<years>(minutes::max()) :
-        year{std::numeric_limits<short>::max()};
+    return year{std::numeric_limits<short>::max()};
 }
 
 CONSTCD11
@@ -2709,7 +2696,7 @@ inline
 days
 year_month_weekday::to_days() const NOEXCEPT
 {
-    auto d = day_point(y_/m_/1);
+    auto d = sys_days(y_/m_/1);
     return (d + (wdi_.weekday() - date::weekday(d) + days{(wdi_.index()-1)*7})
            ).time_since_epoch();
 }
diff --git a/iso_week.h b/iso_week.h
index 9103659..f6afceb 100644
--- a/iso_week.h
+++ b/iso_week.h
@@ -41,9 +41,6 @@ using years = date::years;
 using sys_days = date::sys_days;
 using local_days = date::local_days;
 
-// deprecated:
-using day_point = sys_days;
-
 // types
 
 struct last_week
diff --git a/test/date_test/durations.pass.cpp b/test/date_test/durations.pass.cpp
index 70a152b..2c35e98 100644
--- a/test/date_test/durations.pass.cpp
+++ b/test/date_test/durations.pass.cpp
@@ -36,7 +36,7 @@
 // 
 // time_point
 // 
-// using day_point = std::chrono::time_point<std::chrono::system_clock, days>;
+// using sys_days = std::chrono::time_point<std::chrono::system_clock, days>;
 
 #include "date.h"
 
@@ -54,7 +54,7 @@ static_assert(date::years{400} == date::days{146097}, "");
 static_assert(date::days{365} < date::years{1} && date::years{1} < date::days{366}, "");
 static_assert(date::weeks{52} < date::years{1} && date::years{1} < date::weeks{53}, "");
 
-static_assert(std::is_same<date::day_point::duration, date::days>{}, "");
+static_assert(std::is_same<date::sys_days::duration, date::days>{}, "");
 
 int
 main()
diff --git a/test/date_test/sizeof.pass.cpp b/test/date_test/sizeof.pass.cpp
index 104507c..3df45a1 100644
--- a/test/date_test/sizeof.pass.cpp
+++ b/test/date_test/sizeof.pass.cpp
@@ -34,7 +34,7 @@ main()
     static_assert(sizeof(months)                  == 4, "");
     static_assert(sizeof(years)                   == 4, "");
 
-    static_assert(sizeof(day_point)               == 4, "");
+    static_assert(sizeof(sys_days)               == 4, "");
 
     static_assert(sizeof(last_spec)               == 1, "");
 
diff --git a/test/date_test/weekday.pass.cpp b/test/date_test/weekday.pass.cpp
index bae513b..ed5da17 100644
--- a/test/date_test/weekday.pass.cpp
+++ b/test/date_test/weekday.pass.cpp
@@ -25,7 +25,7 @@
 //     unsigned char wd_;
 // public:
 //     explicit constexpr weekday(unsigned wd) noexcept;
-//     constexpr weekday(const day_point& dp) noexcept;
+//     constexpr weekday(const sys_days& dp) noexcept;
 // 
 //     weekday& operator++()    noexcept;
 //     weekday  operator++(int) noexcept;
@@ -76,10 +76,10 @@ static_assert( std::is_trivially_move_constructible<date::weekday>{}, "");
 static_assert( std::is_trivially_move_assignable<date::weekday>{}, "");
 
 static_assert( std::is_nothrow_constructible<date::weekday, unsigned>{}, "");
-static_assert( std::is_nothrow_constructible<date::weekday, date::day_point>{}, "");
+static_assert( std::is_nothrow_constructible<date::weekday, date::sys_days>{}, "");
 static_assert( std::is_nothrow_constructible<unsigned, date::weekday>{}, "");
 static_assert(!std::is_convertible<unsigned, date::weekday>{}, "");
-static_assert( std::is_convertible<date::day_point, date::weekday>{}, "");
+static_assert( std::is_convertible<date::sys_days, date::weekday>{}, "");
 static_assert(!std::is_convertible<date::weekday, unsigned>{}, "");
 static_assert(static_cast<unsigned>(date::weekday{1u}) == 1, "");
 
diff --git a/test/date_test/year.pass.cpp b/test/date_test/year.pass.cpp
index dfb051b..1b28914 100644
--- a/test/date_test/year.pass.cpp
+++ b/test/date_test/year.pass.cpp
@@ -108,29 +108,29 @@ main()
 
 #if __cplusplus >= 201402
     using int64_t = std::int64_t;
-    static_assert(day_point(year::min()/jan/1)  - day_point(1970_y/jan/1)
+    static_assert(sys_days(year::min()/jan/1)  - sys_days(1970_y/jan/1)
         >= as<int64_t>(days::min()), "");
-    static_assert(day_point(year::min()/jan/1)  - day_point(1970_y/jan/1)
+    static_assert(sys_days(year::min()/jan/1)  - sys_days(1970_y/jan/1)
         >= as<int64_t>(hours::min()), "");
-    static_assert(day_point(year::min()/jan/1)  - day_point(1970_y/jan/1)
+    static_assert(sys_days(year::min()/jan/1)  - sys_days(1970_y/jan/1)
         >= as<int64_t>(minutes::min()), "");
-    static_assert(day_point(year::min()/jan/1)  - day_point(1970_y/jan/1)
+    static_assert(sys_days(year::min()/jan/1)  - sys_days(1970_y/jan/1)
         >= as<int64_t>(seconds::min()), "");
-    static_assert(day_point(year::min()/jan/1)  - day_point(1970_y/jan/1)
+    static_assert(sys_days(year::min()/jan/1)  - sys_days(1970_y/jan/1)
         >= as<int64_t>(milliseconds::min()), "");
-    static_assert(day_point(year::min()/jan/1)  - day_point(1970_y/jan/1)
+    static_assert(sys_days(year::min()/jan/1)  - sys_days(1970_y/jan/1)
         >= as<int64_t>(microseconds::min()), "");
-    static_assert(day_point(year::max()/dec/31) - day_point(1970_y/jan/1)
+    static_assert(sys_days(year::max()/dec/31) - sys_days(1970_y/jan/1)
         <= as<int64_t>(microseconds::max()), "");
-    static_assert(day_point(year::max()/dec/31) - day_point(1970_y/jan/1)
+    static_assert(sys_days(year::max()/dec/31) - sys_days(1970_y/jan/1)
         <= as<int64_t>(milliseconds::max()), "");
-    static_assert(day_point(year::max()/dec/31) - day_point(1970_y/jan/1)
+    static_assert(sys_days(year::max()/dec/31) - sys_days(1970_y/jan/1)
         <= as<int64_t>(seconds::max()), "");
-    static_assert(day_point(year::max()/dec/31) - day_point(1970_y/jan/1)
+    static_assert(sys_days(year::max()/dec/31) - sys_days(1970_y/jan/1)
         <= as<int64_t>(minutes::max()), "");
-    static_assert(day_point(year::max()/dec/31) - day_point(1970_y/jan/1)
+    static_assert(sys_days(year::max()/dec/31) - sys_days(1970_y/jan/1)
         <= as<int64_t>(hours::max()), "");
-    static_assert(day_point(year::max()/dec/31) - day_point(1970_y/jan/1)
+    static_assert(sys_days(year::max()/dec/31) - sys_days(1970_y/jan/1)
         <= as<int64_t>(days::max()), "");
 #endif
 
diff --git a/test/date_test/year_month_day.pass.cpp b/test/date_test/year_month_day.pass.cpp
index ef93ac6..792253e 100644
--- a/test/date_test/year_month_day.pass.cpp
+++ b/test/date_test/year_month_day.pass.cpp
@@ -26,7 +26,7 @@
 //     constexpr year_month_day(const date::year& y, const date::month& m,
 //                                const date::day& d) noexcept;
 //     constexpr year_month_day(const year_month_day_last& ymdl) noexcept;
-//     constexpr year_month_day(const day_point& dp) noexcept;
+//     constexpr year_month_day(const sys_days& dp) noexcept;
 // 
 //     year_month_day& operator+=(const months& m) noexcept;
 //     year_month_day& operator-=(const months& m) noexcept;
@@ -37,7 +37,7 @@
 //     constexpr date::month month() const noexcept;
 //     constexpr date::day   day()   const noexcept;
 // 
-//     constexpr operator day_point() const noexcept;
+//     constexpr operator sys_days() const noexcept;
 //     constexpr bool ok() const noexcept;
 // };
 
@@ -76,10 +76,10 @@ static_assert(std::is_nothrow_constructible<date::year_month_day, date::year,
 static_assert(std::is_nothrow_constructible<date::year_month_day,
                                             date::year_month_day_last>{}, "");
 static_assert(std::is_convertible<date::year_month_day_last, date::year_month_day>{}, "");
-static_assert(std::is_nothrow_constructible<date::year_month_day, date::day_point>{}, "");
-static_assert(std::is_convertible<date::day_point, date::year_month_day>{}, "");
-static_assert(std::is_nothrow_constructible<date::day_point, date::year_month_day>{}, "");
-static_assert(std::is_convertible<date::year_month_day, date::day_point>{}, "");
+static_assert(std::is_nothrow_constructible<date::year_month_day, date::sys_days>{}, "");
+static_assert(std::is_convertible<date::sys_days, date::year_month_day>{}, "");
+static_assert(std::is_nothrow_constructible<date::sys_days, date::year_month_day>{}, "");
+static_assert(std::is_convertible<date::year_month_day, date::sys_days>{}, "");
 
 void
 test_arithmetic()
@@ -131,7 +131,7 @@ test_day_point_conversion()
     using namespace date;
     year y   = year{-1000};
     year end =       3000_y;
-    day_point prev_dp = day_point(year_month_day{y, jan, 1_d}) - days{1};
+    sys_days prev_dp = sys_days(year_month_day{y, jan, 1_d}) - days{1};
     weekday   prev_wd = weekday{prev_dp};
     for (; y <= end; ++y)
     {
@@ -143,7 +143,7 @@ test_day_point_conversion()
             {
                 year_month_day ymd = {y, m, d};
                 assert(ymd.ok());
-                day_point dp = ymd;
+                sys_days dp = ymd;
                 assert(dp == prev_dp + days{1});
                 year_month_day ymd2 = dp;
                 assert(ymd2 == ymd);
@@ -171,7 +171,7 @@ main()
     static_assert(ymd1.day() == 9_d, "");
 
 #if __cplusplus >= 201402
-    constexpr day_point dp = ymd1;
+    constexpr sys_days dp = ymd1;
     static_assert(dp.time_since_epoch() == days{16656}, "");
     constexpr year_month_day ymd2 = dp;
     static_assert(ymd1 == ymd2, "");
@@ -186,7 +186,7 @@ main()
     static_assert(ymd3.day() == 31_d, "");
 
 #if __cplusplus >= 201402
-    constexpr day_point dp3 = ymd3;
+    constexpr sys_days dp3 = ymd3;
     static_assert(dp3.time_since_epoch() == days{-1}, "");
     constexpr year_month_day ymd4 = dp3;
     static_assert(ymd3 == ymd4, "");
@@ -211,9 +211,9 @@ main()
     static_assert( (2100_y/feb/28).ok(), "");
     static_assert(!(2100_y/feb/29).ok(), "");
 
-    static_assert(day_point(2100_y/feb/28) + days{1} == day_point(2100_y/mar/1), "");
-    static_assert(day_point(2000_y/mar/1) - day_point(2000_y/feb/28) == days{2}, "");
-    static_assert(day_point(2100_y/mar/1) - day_point(2100_y/feb/28) == days{1}, "");
+    static_assert(sys_days(2100_y/feb/28) + days{1} == sys_days(2100_y/mar/1), "");
+    static_assert(sys_days(2000_y/mar/1) - sys_days(2000_y/feb/28) == days{2}, "");
+    static_assert(sys_days(2100_y/mar/1) - sys_days(2100_y/feb/28) == days{1}, "");
 
     static_assert(jan/31/2015 == jan/last/2015, "");
     static_assert(feb/28/2015 == feb/last/2015, "");
diff --git a/test/date_test/year_month_day_last.pass.cpp b/test/date_test/year_month_day_last.pass.cpp
index fdd1df0..6ac800a 100644
--- a/test/date_test/year_month_day_last.pass.cpp
+++ b/test/date_test/year_month_day_last.pass.cpp
@@ -36,7 +36,7 @@
 //     constexpr date::month_day_last month_day_last() const noexcept;
 //     constexpr date::day            day()            const noexcept;
 // 
-//     constexpr operator day_point() const noexcept;
+//     constexpr operator sys_days() const noexcept;
 //     constexpr bool ok() const noexcept;
 // };
 
@@ -94,9 +94,9 @@ static_assert( std::is_trivially_move_assignable<date::year_month_day_last>{}, "
 
 static_assert(std::is_nothrow_constructible<date::year_month_day_last,
                                                 date::year, date::month_day_last>{}, "");
-static_assert(std::is_nothrow_constructible<date::day_point,
+static_assert(std::is_nothrow_constructible<date::sys_days,
                                                 date::year_month_day_last>{}, "");
-static_assert(std::is_convertible<date::year_month_day_last, date::day_point>{}, "");
+static_assert(std::is_convertible<date::year_month_day_last, date::sys_days>{}, "");
 
 void
 test_arithmetic()
@@ -154,7 +154,7 @@ main()
     static_assert(ymdl1.month_day_last() == month_day_last{aug}, "");
 #if __cplusplus >= 201402
     static_assert(ymdl1.day() == 31_d, "");
-    constexpr day_point dp = ymdl1;
+    constexpr sys_days dp = ymdl1;
     constexpr year_month_day ymd = dp;
     static_assert(ymd == 2015_y/aug/31, "");
 #endif
diff --git a/test/date_test/year_month_weekday.pass.cpp b/test/date_test/year_month_weekday.pass.cpp
index b3a00de..70fefa0 100644
--- a/test/date_test/year_month_weekday.pass.cpp
+++ b/test/date_test/year_month_weekday.pass.cpp
@@ -25,7 +25,7 @@
 // public:
 //     constexpr year_month_weekday(const date::year& y, const date::month& m,
 //                                    const date::weekday_indexed& wdi) noexcept;
-//     constexpr year_month_weekday(const day_point& dp) noexcept;
+//     constexpr year_month_weekday(const sys_days& dp) noexcept;
 // 
 //     year_month_weekday& operator+=(const months& m) noexcept;
 //     year_month_weekday& operator-=(const months& m) noexcept;
@@ -38,11 +38,11 @@
 //     constexpr unsigned index() const noexcept;
 //     constexpr date::weekday_indexed weekday_indexed() const noexcept;
 // 
-//     constexpr operator day_point() const noexcept;
+//     constexpr operator sys_days() const noexcept;
 //     constexpr bool ok() const noexcept;
 // 
 // private:
-//     static constexpr year_month_weekday from_day_point(const day_point& dp) noexcept;
+//     static constexpr year_month_weekday from_day_point(const sys_days& dp) noexcept;
 // };
 
 // constexpr
@@ -93,11 +93,11 @@ static_assert(std::is_nothrow_constructible<date::year_month_weekday,
                                                 date::year, date::month,
                                                 date::weekday_indexed>{}, "");
 static_assert(std::is_nothrow_constructible<date::year_month_weekday,
-                                                date::day_point>{}, "");
-static_assert(std::is_convertible<date::day_point, date::year_month_weekday>{}, "");
-static_assert(std::is_nothrow_constructible<date::day_point,
+                                                date::sys_days>{}, "");
+static_assert(std::is_convertible<date::sys_days, date::year_month_weekday>{}, "");
+static_assert(std::is_nothrow_constructible<date::sys_days,
                                                 date::year_month_weekday>{}, "");
-static_assert(std::is_convertible<date::year_month_weekday, date::day_point>{}, "");
+static_assert(std::is_convertible<date::year_month_weekday, date::sys_days>{}, "");
 
 void
 test_arithmetic()
@@ -158,7 +158,7 @@ main()
     static_assert(ymdl1.index() == 2u, "");
     static_assert(ymdl1.weekday_indexed() == fri[2], "");
 #if __cplusplus >= 201402
-    constexpr day_point dp = ymdl1;
+    constexpr sys_days dp = ymdl1;
     constexpr year_month_day ymd = dp;
     static_assert(ymd == 2015_y/aug/14, "");
 #endif
diff --git a/test/date_test/year_month_weekday_last.pass.cpp b/test/date_test/year_month_weekday_last.pass.cpp
index 08a0e44..843df17 100644
--- a/test/date_test/year_month_weekday_last.pass.cpp
+++ b/test/date_test/year_month_weekday_last.pass.cpp
@@ -36,7 +36,7 @@
 //     constexpr date::weekday weekday() const noexcept;
 //     constexpr date::weekday_last weekday_last() const noexcept;
 // 
-//     constexpr operator day_point() const noexcept;
+//     constexpr operator sys_days() const noexcept;
 //     constexpr bool ok() const noexcept;
 // };
 
@@ -90,9 +90,9 @@ static_assert( std::is_trivially_move_assignable<date::year_month_weekday_last>{
 static_assert(std::is_nothrow_constructible<date::year_month_weekday_last,
                                                 date::year, date::month,
                                                 date::weekday_last>{}, "");
-static_assert(std::is_nothrow_constructible<date::day_point,
+static_assert(std::is_nothrow_constructible<date::sys_days,
                                                 date::year_month_weekday_last>{}, "");
-static_assert(std::is_convertible<date::year_month_weekday_last, date::day_point>{}, "");
+static_assert(std::is_convertible<date::year_month_weekday_last, date::sys_days>{}, "");
 
 void
 test_arithmetic()
@@ -150,7 +150,7 @@ main()
     static_assert(ymdl1.weekday() == fri, "");
     static_assert(ymdl1.weekday_last() == fri[last], "");
 #if __cplusplus >= 201402
-    constexpr day_point dp = ymdl1;
+    constexpr sys_days dp = ymdl1;
     constexpr year_month_day ymd = dp;
     static_assert(ymd == 2015_y/aug/28, "");
 #endif
diff --git a/test/iso_week/weekday.pass.cpp b/test/iso_week/weekday.pass.cpp
index 9c84c9b..702cdc4 100644
--- a/test/iso_week/weekday.pass.cpp
+++ b/test/iso_week/weekday.pass.cpp
@@ -26,7 +26,7 @@
 // public:
 //     explicit constexpr weekday(unsigned wd) noexcept;
 //     constexpr weekday(date::weekday wd) noexcept;
-//     constexpr weekday(const day_point& dp) noexcept;
+//     constexpr weekday(const sys_days& dp) noexcept;
 // 
 //     weekday& operator++()    noexcept;
 //     weekday  operator++(int) noexcept;
@@ -85,12 +85,12 @@ static_assert(std::is_standard_layout<iso_week::weekday>{}, "");
 static_assert(std::is_literal_type<iso_week::weekday>{}, "");
 
 static_assert( std::is_nothrow_constructible<iso_week::weekday, unsigned>{}, "");
-static_assert( std::is_nothrow_constructible<iso_week::weekday, iso_week::day_point>{}, "");
+static_assert( std::is_nothrow_constructible<iso_week::weekday, iso_week::sys_days>{}, "");
 static_assert( std::is_nothrow_constructible<iso_week::weekday, date::weekday>{}, "");
 static_assert( std::is_nothrow_constructible<date::weekday, iso_week::weekday>{}, "");
 static_assert( std::is_nothrow_constructible<unsigned, iso_week::weekday>{}, "");
 static_assert(!std::is_convertible<unsigned, iso_week::weekday>{}, "");
-static_assert( std::is_convertible<iso_week::day_point, iso_week::weekday>{}, "");
+static_assert( std::is_convertible<iso_week::sys_days, iso_week::weekday>{}, "");
 static_assert( std::is_convertible<iso_week::weekday, date::weekday>{}, "");
 static_assert( std::is_convertible<date::weekday, iso_week::weekday>{}, "");
 static_assert(!std::is_convertible<iso_week::weekday, unsigned>{}, "");
diff --git a/test/iso_week/year_lastweek_weekday.pass.cpp b/test/iso_week/year_lastweek_weekday.pass.cpp
index 59a43aa..e2164a4 100644
--- a/test/iso_week/year_lastweek_weekday.pass.cpp
+++ b/test/iso_week/year_lastweek_weekday.pass.cpp
@@ -33,7 +33,7 @@
 //     constexpr iso_week::weeknum weeknum() const noexcept;
 //     constexpr iso_week::weekday weekday() const noexcept;
 // 
-//     constexpr operator day_point() const noexcept;
+//     constexpr operator sys_days() const noexcept;
 //     constexpr bool ok() const noexcept;
 // };
 // 
@@ -69,10 +69,10 @@ static_assert(std::is_literal_type<iso_week::year_lastweek_weekday>{}, "");
 
 static_assert( std::is_nothrow_constructible<iso_week::year_lastweek_weekday,
                                                  iso_week::year, iso_week::weekday>{}, "");
-static_assert( std::is_nothrow_constructible<iso_week::day_point,
+static_assert( std::is_nothrow_constructible<iso_week::sys_days,
                                                  iso_week::year_lastweek_weekday>{}, "");
 static_assert( std::is_convertible<iso_week::year_lastweek_weekday,
-                                       iso_week::day_point>{}, "");
+                                       iso_week::sys_days>{}, "");
 
 int
 main()
@@ -100,8 +100,8 @@ main()
     assert(x3.weeknum() == 53_w);
     assert(x3.weekday() == tue);
 
-    constexpr day_point dp = 2015_y/last/wed;
-    static_assert(dp == day_point{days{16799}}, "");
+    constexpr sys_days dp = 2015_y/last/wed;
+    static_assert(dp == sys_days{days{16799}}, "");
 
     static_assert(x0.ok(), "");
     assert(x3.ok());
diff --git a/test/iso_week/year_weeknum_weekday.pass.cpp b/test/iso_week/year_weeknum_weekday.pass.cpp
index 4b4a726..02e6420 100644
--- a/test/iso_week/year_weeknum_weekday.pass.cpp
+++ b/test/iso_week/year_weeknum_weekday.pass.cpp
@@ -28,7 +28,7 @@
 //     constexpr year_weeknum_weekday(const iso_week::year& y, const iso_week::weeknum& wn,
 //                                    const iso_week::weekday& wd) noexcept;
 //     constexpr year_weeknum_weekday(const year_lastweek_weekday& ylwwd) noexcept;
-//     constexpr year_weeknum_weekday(const day_point& dp) noexcept;
+//     constexpr year_weeknum_weekday(const sys_days& dp) noexcept;
 // 
 //     year_weeknum_weekday& operator+=(const years& y) noexcept;
 //     year_weeknum_weekday& operator-=(const years& y) noexcept;
@@ -37,7 +37,7 @@
 //     constexpr iso_week::weeknum weeknum() const noexcept;
 //     constexpr iso_week::weekday weekday() const noexcept;
 // 
-//     constexpr operator day_point() const noexcept;
+//     constexpr operator sys_days() const noexcept;
 //     constexpr bool ok() const noexcept;
 // };
 // 
@@ -79,13 +79,13 @@ static_assert( std::is_nothrow_constructible<iso_week::year_weeknum_weekday,
 static_assert( std::is_convertible<iso_week::year_lastweek_weekday,
                                        iso_week::year_weeknum_weekday>{}, "");
 static_assert( std::is_nothrow_constructible<iso_week::year_weeknum_weekday,
-                                                 iso_week::day_point>{}, "");
-static_assert( std::is_convertible<iso_week::day_point,
+                                                 iso_week::sys_days>{}, "");
+static_assert( std::is_convertible<iso_week::sys_days,
                                        iso_week::year_weeknum_weekday>{}, "");
-static_assert( std::is_nothrow_constructible<iso_week::day_point,
+static_assert( std::is_nothrow_constructible<iso_week::sys_days,
                                                  iso_week::year_weeknum_weekday>{}, "");
 static_assert( std::is_convertible<iso_week::year_weeknum_weekday,
-                                       iso_week::day_point>{}, "");
+                                       iso_week::sys_days>{}, "");
 
 int
 main()
@@ -102,7 +102,7 @@ main()
     static_assert(x1.weeknum() == 53_w, "");
     static_assert(x1.weekday() == tue, "");
 
-    constexpr year_weeknum_weekday x2 = day_point{days{16792}};
+    constexpr year_weeknum_weekday x2 = sys_days{days{16792}};
     static_assert(x2.year() == 2015_y, "");
     static_assert(x2.weeknum() == 52_w, "");
     static_assert(x2.weekday() == wed, "");
@@ -118,8 +118,8 @@ main()
     assert(x3.weeknum() == 52_w);
     assert(x3.weekday() == wed);
 
-    constexpr day_point dp = 2015_y/52_w/wed;
-    static_assert(dp == day_point{days{16792}}, "");
+    constexpr sys_days dp = 2015_y/52_w/wed;
+    static_assert(dp == sys_days{days{16792}}, "");
 
     static_assert(x0.ok(), "");
     static_assert(x1.ok(), "");
diff --git a/tz.h b/tz.h
index 406d622..0ebc4a7 100644
--- a/tz.h
+++ b/tz.h
@@ -223,36 +223,6 @@ operator<<(std::ostream& os, const local_info& r);
 using Info = sys_info;
 
 class time_zone;
-// deprecated:
-using Zone = time_zone;
-
-namespace detail
-{
-
-inline
-days
-sum()
-{
-    return days{0};
-}
-
-template <class Duration>
-inline
-Duration
-sum(Duration d)
-{
-    return d;
-}
-
-template <class D1, class D2, class... Durations>
-inline
-std::common_type_t<D1, D2, Durations...>
-sum(D1 d1, D2 d2, Durations ...durations)
-{
-    return d1 + d2 + sum(durations...);
-}
-
-}  // detail
 
 template <class Duration>
 class zoned_time