Switched to the MIT license with an optional exception that allows distributing binary code without attribution.

Floating-point formatting is now locale-independent by default:

#include <locale>
#include <fmt/core.h>

int main() {
  std::locale::global(std::locale("ru_RU.UTF-8"));
  fmt::print("value = {}", 4.2);
}

prints "value = 4.2" regardless of the locale. For locale-specific formatting use the n specifier:

std::locale::global(std::locale("ru_RU.UTF-8"));
fmt::print("value = {:n}", 4.2);

prints "value = 4,2".

Added an experimental Grisu floating-point formatting algorithm implementation (disabled by default). To enable it compile with the FMT_USE_GRISU macro defined to 1:

#define FMT_USE_GRISU 1
#include <fmt/format.h>

auto s = fmt::format("{}", 4.2); // formats 4.2 using Grisu

With Grisu enabled, {fmt} is 13x faster than std::ostringstream (libc++) and 10x faster than sprintf on dtoa-benchmark (full results):

Separated formatting and parsing contexts for consistency with C++20 std::format, removing the undocumented basic_format_context::parse_context() function.

Added oss-fuzz support (#1199). Thanks @pauldreik (Paul Dreik).

formatter specializations now always take precedence over operator<< (#952):

#include <iostream>
#include <fmt/ostream.h>

struct S {};

std::ostream& operator<<(std::ostream& os, S) {
  return os << 1;
}

template <>
struct fmt::formatter<S> : fmt::formatter<int> {
  auto format(S, format_context& ctx) {
    return formatter<int>::format(2, ctx);
  }
};

int main() {
  std::cout << S() << "\n"; // prints 1 using operator<<
  fmt::print("{}\n", S());  // prints 2 using formatter
}

Introduced the experimental fmt::compile function that does format string compilation (#618, #1169, #1171):

#include <fmt/compile.h>

auto f = fmt::compile<int>("{}");
std::string s = fmt::format(f, 42); // can be called multiple times to format
                                    // different values
// s == "42"

It moves the cost of parsing a format string outside of the format function which can be beneficial when identically formatting many objects of the same types. Thanks @stryku (Mateusz Janek).

Added experimental support for the % format specifier that formats floating-point values as percentages (#1060, #1069, #1071):

auto s = fmt::format("{:.1%}", 0.42); // s == "42.0%"

Thanks @gawain-bolton (Gawain Bolton).

Implemented precision for floating-point durations (#1004, #1012):

auto s = fmt::format("{:.1}", std::chrono::duration<double>(1.234));
// s == 1.2s

Thanks @DanielaE (Daniela Engert).

Implemented chrono format specifiers %Q and %q that give the value and the unit respectively (#1019):

auto value = fmt::format("{:%Q}", 42s); // value == "42"
auto unit  = fmt::format("{:%q}", 42s); // unit == "s"

Thanks @DanielaE (Daniela Engert).

Fixed handling of dynamic width in chrono formatter:

auto s = fmt::format("{0:{1}%H:%M:%S}", std::chrono::seconds(12345), 12);
//                        ^ width argument index                     ^ width
// s == "03:25:45    "

Thanks Howard Hinnant.

Removed deprecated fmt/time.h. Use fmt/chrono.h instead.

Added fmt::format and fmt::vformat overloads that take text_style (#993, #994):

#include <fmt/color.h>

std::string message = fmt::format(fmt::emphasis::bold | fg(fmt::color::red),
                                  "The answer is {}.", 42);

Thanks @Naios (Denis Blank).

Removed the deprecated color API (print_colored). Use the new API, namely print overloads that take text_style instead.

Made std::unique_ptr and std::shared_ptr formattable as pointers via fmt::ptr (#1121):

std::unique_ptr<int> p = ...;
fmt::print("{}", fmt::ptr(p)); // prints p as a pointer

Thanks @sighingnow (Tao He).

Made print and vprint report I/O errors (#1098, #1099). Thanks @BillyDonahue (Billy Donahue).

Marked deprecated APIs with the [[deprecated]] attribute and removed internal uses of deprecated APIs (#1022). Thanks @eliaskosunen (Elias Kosunen).

Modernized the codebase using more C++11 features and removing workarounds. Most importantly, buffer_context is now an alias template, so use buffer_context<T> instead of buffer_context<T>::type. These features require GCC 4.8 or later.

formatter specializations now always take precedence over implicit conversions to int and the undocumented convert_to_int trait is now deprecated.

Moved the undocumented basic_writer, writer, and wwriter types to the internal namespace.

Removed deprecated basic_format_context::begin(). Use out() instead.

Disallowed passing the result of join as an lvalue to prevent misuse.

Refactored the undocumented structs that represent parsed format specifiers to simplify the API and allow multibyte fill.

Moved SFINAE to template parameters to reduce symbol sizes.

Switched to fputws for writing wide strings so that it's no longer required to call _setmode on Windows (#1229, #1243). Thanks @jackoalan (Jack Andersen).

Improved literal-based API (#1254). Thanks @sylveon (Charles Milette).

Added support for exotic platforms without uintptr_t such as IBM i (AS/400) which has 128-bit pointers and only 64-bit integers (#1059).

Added Sublime Text syntax highlighting config (#1037). Thanks @Kronuz (Germán Méndez Bravo).

Added the FMT_ENFORCE_COMPILE_STRING macro to enforce the use of compile-time format strings (#1231). Thanks @jackoalan (Jack Andersen).

Stopped setting CMAKE_BUILD_TYPE if {fmt} is a subproject (#1081).

Various build improvements (#1039, #1078, #1091, #1103, #1177). Thanks @luncliff (Park DongHa), @jasonszang (Jason Shuo Zang), @olafhering (Olaf Hering), @Lecetem, @pauldreik (Paul Dreik).

Improved documentation (#1049, #1051, #1083, #1113, #1114, #1146, #1180, #1250, #1252, #1265). Thanks @mikelui (Michael Lui), @foonathan (Jonathan Müller), @BillyDonahue (Billy Donahue), @jwakely (Jonathan Wakely), @kaisbe (Kais Ben Salah), @sdebionne (Samuel Debionne).

Fixed ambiguous formatter specialization in fmt/ranges.h (#1123).

Fixed formatting of a non-empty std::filesystem::path which is an infinitely deep range of its components (#1268).

Fixed handling of general output iterators when formatting characters (#1056, #1058). Thanks @abolz (Alexander Bolz).

Fixed handling of output iterators in formatter specialization for ranges (#1064).

Fixed handling of exotic character types (#1188).

Made chrono formatting work with exceptions disabled (#1062).

Fixed DLL visibility issues (#1134, #1147). Thanks @denchat.

Disabled the use of UDL template extension on GCC 9 (#1148).

Removed misplaced format compile-time checks from printf (#1173).

Fixed issues in the experimental floating-point formatter (#1072, #1129, #1153, #1155, #1210, #1222). Thanks @alabuzhev (Alex Alabuzhev).

Fixed bugs discovered by fuzzing or during fuzzing integration (#1124, #1127, #1132, #1135, #1136, #1141, #1142, #1178, #1179, #1194). Thanks @pauldreik (Paul Dreik).

Fixed building tests on FreeBSD and Hurd (#1043). Thanks @jackyf (Eugene V. Lyubimkin).

Fixed various warnings and compilation issues (#998, #1006, #1008, #1011, #1025, #1027, #1028, #1029, #1030, #1031, #1054, #1063, #1068, #1074, #1075, #1079, #1086, #1088, #1089, #1094, #1101, #1102, #1105, #1107, #1115, #1117, #1118, #1120, #1123, #1139, #1140, #1143, #1144, #1150, #1151, #1152, #1154, #1156, #1159, #1175, #1181, #1186, #1187, #1191, #1197, #1200, #1203, #1205, #1206, #1213, #1214, #1217, #1228, #1230, #1232, #1235, #1236, #1240). Thanks @DanielaE (Daniela Engert), @mwinterb, @eliaskosunen (Elias Kosunen), @morinmorin, @ricco19 (Brian Ricciardelli), @waywardmonkeys (Bruce Mitchener), @chronoxor (Ivan Shynkarenka), @remyabel, @pauldreik (Paul Dreik), @gsjaardema (Greg Sjaardema), @rcane (Ronny Krüger), @mocabe, @denchat, @cjdb (Christopher Di Bella), @HazardyKnusperkeks (Björn Schäpers), @vedranmiletic (Vedran Miletić), @jackoalan (Jack Andersen), @DaanDeMeyer (Daan De Meyer), @starkmapper (Mark Stapper).