Introduced experimental chrono formatting support:

#include <fmt/chrono.h>

int main() {
  using namespace std::literals::chrono_literals;
  fmt::print("Default format: {} {}\n", 42s, 100ms);
  fmt::print("strftime-like format: {:%H:%M:%S}\n", 3h + 15min + 30s);
}

prints:

Default format: 42s 100ms
strftime-like format: 03:15:30

Added experimental support for emphasis (bold, italic, underline, strikethrough), colored output to a file stream, and improved colored formatting API (#961, #967, #973):

#include <fmt/color.h>

int main() {
  print(fg(fmt::color::crimson) | fmt::emphasis::bold,
        "Hello, {}!\n", "world");
  print(fg(fmt::color::floral_white) | bg(fmt::color::slate_gray) |
        fmt::emphasis::underline, "Hello, {}!\n", "мир");
  print(fg(fmt::color::steel_blue) | fmt::emphasis::italic,
        "Hello, {}!\n", "世界");
}

prints the following on modern terminals with RGB color support:

Thanks @Rakete1111 (Nicolas).

Added support for 4-bit terminal colors (#968, #974)

#include <fmt/color.h>

int main() {
  print(fg(fmt::terminal_color::red), "stop\n");
}

Note that these colors vary by terminal:Thanks @Rakete1111 (Nicolas).

Parameterized formatting functions on the type of the format string (#880, #881, #883, #885, #897, #920). Any object of type S that has an overloaded to_string_view(const S&) returning fmt::string_view can be used as a format string:

namespace my_ns {
inline string_view to_string_view(const my_string& s) {
  return {s.data(), s.length()};
}
}

std::string message = fmt::format(my_string("The answer is {}."), 42);

Thanks @DanielaE (Daniela Engert).

Made std::string_view work as a format string (#898):

auto message = fmt::format(std::string_view("The answer is {}."), 42);

Thanks @DanielaE (Daniela Engert).

Added wide string support to compile-time format string checks (#924):

print(fmt(L"{:f}"), 42); // compile-time error: invalid type specifier

Thanks @XZiar.

Made colored print functions work with wide strings (#867):

#include <fmt/color.h>

int main() {
  print(fg(fmt::color::red), L"{}\n", 42);
}

Thanks @DanielaE (Daniela Engert).

Introduced experimental Unicode support (#628, #891):

using namespace fmt::literals;
auto s = fmt::format("{:*^5}"_u, "🤡"_u); // s == "**🤡**"_u

Improved locale support:

#include <fmt/locale.h>

struct numpunct : std::numpunct<char> {
 protected:
  char do_thousands_sep() const override { return '~'; }
};

std::locale loc;
auto s = fmt::format(std::locale(loc, new numpunct()), "{:n}", 1234567);
// s == "1~234~567"

Constrained formatting functions on proper iterator types (#921). Thanks @DanielaE (Daniela Engert).

Added make_printf_args and make_wprintf_args functions (#934). Thanks @tnovotny.

Deprecated fmt::visit, parse_context, and wparse_context. Use fmt::visit_format_arg, format_parse_context, and wformat_parse_context instead.

Removed undocumented basic_fixed_buffer which has been superseded by the iterator-based API (#873, #902). Thanks @superfunc (hollywood programmer).

Disallowed repeated leading zeros in an argument ID:

fmt::print("{000}", 42); // error

Reintroduced support for gcc 4.4.

Fixed compilation on platforms with exotic double (#878).

Improved documentation (#164, #877, #901, #906, #979). Thanks @kookjr (Mathew Cucuzella), @DarkDimius (Dmitry Petrashko), @HecticSerenity.

Added pkgconfig support which makes it easier to consume the library from meson and other build systems (#916). Thanks @colemickens (Cole Mickens).

Various build improvements (#909, #926, #937, #953, #959). Thanks @tchaikov (Kefu Chai), @luncliff (Park DongHa), @AndreasSchoenle (Andreas Schönle), @hotwatermorning, @Zefz (JohanJansen).

Improved string_view construction performance (#914). Thanks @gabime (Gabi Melman).

Fixed non-matching char types (#895). Thanks @DanielaE (Daniela Engert).

Fixed format_to_n with std::back_insert_iterator (#913). Thanks @DanielaE (Daniela Engert).

Fixed locale-dependent formatting (#905).

Fixed various compiler warnings and errors (#882, #886, #933, #941, #931, #943, #954, #956, #962, #965, #977, #983, #989). Thanks @Luthaf (Guillaume Fraux), @stevenhoving (Steven Hoving), @christinaa (Kristina Brooks), @lgritz (Larry Gritz), @DanielaE (Daniela Engert), @0x8000-0000 (Sign Bit), @liuping1997.